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RFC 7681


Independent Submission                                          J. Davin
Request for Comments: 7681                                  October 2015
Category: Informational
ISSN: 2070-1721

             Email Exchange of Secondary School Transcripts

Abstract

   A common format simplifies exchange of secondary school academic
   transcripts via electronic mail.  Existing standards are applied to
   prevent unauthorized alteration of transcript content and to deliver
   transcripts directly and securely from each student to his or her
   chosen recipients.  By eliminating third-party intervention and
   surveillance, the defined protocol better protects student privacy
   and independence than does current practice.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7681.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Design Motivation . . . . . . . . . . . . . . . . . . . . . .   6
   3.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .   8
     3.1.  Student and Originator  . . . . . . . . . . . . . . . . .   8
       3.1.1.  Transcript Requests . . . . . . . . . . . . . . . . .   9
     3.2.  Student and Recipient . . . . . . . . . . . . . . . . . .  10
   4.  Transcript Content  . . . . . . . . . . . . . . . . . . . . .  13
     4.1.  School Transcript Preface . . . . . . . . . . . . . . . .  17
     4.2.  Computational School Transcript . . . . . . . . . . . . .  17
     4.3.  Display School Transcript . . . . . . . . . . . . . . . .  20
   5.  Signed School Transcript  . . . . . . . . . . . . . . . . . .  21
   6.  Transcript Transmission . . . . . . . . . . . . . . . . . . .  24
     6.1.  Encrypted Format  . . . . . . . . . . . . . . . . . . . .  27
     6.2.  Encrypted and Signed Format . . . . . . . . . . . . . . .  28
     6.3.  Encrypted File Format . . . . . . . . . . . . . . . . . .  30
     6.4.  Traditional Inline Format . . . . . . . . . . . . . . . .  33
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  34
     7.1.  Originator Private Key  . . . . . . . . . . . . . . . . .  35
     7.2.  Originator Public Key . . . . . . . . . . . . . . . . . .  35
     7.3.  Originator Certification  . . . . . . . . . . . . . . . .  35
     7.4.  Recipient Public Key  . . . . . . . . . . . . . . . . . .  35
     7.5.  Secure Clients  . . . . . . . . . . . . . . . . . . . . .  36
     7.6.  Automatic Replies . . . . . . . . . . . . . . . . . . . .  36
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  36
     8.1.  Registration of Eesst-Version Header  . . . . . . . . . .  37
     8.2.  Registration of Organization Header . . . . . . . . . . .  37
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  38
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  38
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  38
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  40
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  40

1.  Introduction

   Traditional, paper-based communication of individual student records
   protects the rights and interests of all stakeholders -- the
   secondary school officials who curate student records, the students
   who are both the subjects and distributors of their own individual
   records, and the college admission officers, prospective employers,
   and others who, with the permission of individual students, receive
   and review such records.  In the traditional process, when a
   graduating student applies for employment or admission to an
   institution of higher learning, she asks the guidance counselor at
   her secondary school for a transcript of her academic achievements to
   support her application.  In response, the guidance counselor
   prepares a paper record of that student's achievements and presents

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   it to her so that she might forward that transcript to whomever she
   pleases.  In order to prevent forgery of academic transcripts, the
   paper record presented to the student often includes various marks of
   its authenticity, such as an imprint of the school seal or the
   signature of an authorized school official.  In order to prevent
   unauthorized alteration of transcript content, the prepared document
   is sometimes presented to the student inside a sealed postal envelope
   that cannot easily be opened without detection -- perhaps aided by
   tamper-proof tape, signed envelope flaps, or even imprinted wax
   seals.  The integrity of the envelope's physical seal assures the
   recipient that its contents have not been altered in transit; seals
   and signatures affixed to the enclosed document assure the recipient
   of the transcript's legitimacy.  The student's privacy is assured by
   her ability to forward the sealed transcript to whomever she pleases
   without the knowledge of or further consultation with the school.

                                                              +++
                                                             /   \
           /\     Digital Transcript                        /     \
          /  \    Via Web or Database Connection           /       \
         / 88 \                                           /         \
        /  88  \                \\ //                     | College |
       /        \               (---)  +-------------->>  |         |
       | School | +--------->>  (###)                     +---------+
       |        |                | |
       +--------+         <<... |   |  Copies of Digital Transcript
   School Guidance Dept        \@| |@   Via Web or Database Connection
                                 | |
                                 + +  +-------+                 +++
                                              +------------>>  /   \
                      Third-Party Processor                   /     \
                      Monitors and Controls                  /       \
                      Student Communication                 /         \
                                                            | College |
                                                            |         |
                                                            +---------+

   Figure 1: Corrupted Model for Exchanging Secondary School Transcripts

   While the traditional process of distributing academic transcripts
   admirably protects student privacy and prerogatives, that process
   also requires manual effort from the school staff for the preparation
   of each transcript.  On the premise of reducing that effort, some
   school officials have gratuitously misapplied technology in a way
   that guts student privacy and effectively excludes students from
   their own business.  Figure 1 illustrates an increasingly common
   aberration.  Rather than adopting standardized, readily available
   technology to protect the integrity of transmitted student data -- as

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   it had once been protected by their own signatures on sealed
   envelopes -- school officials interpose themselves (or their agents)
   between students and transcript recipients, claiming falsely that no
   other approach adequately assures the confidentiality, origin, and
   integrity of transcript content or the reliability of transcript
   transmission.  By introducing the role of "third-party processor" in
   Figure 1, educators disrupt what should be private, bilateral
   relationships between students and their chosen correspondents,
   implicitly denying the legitimacy of any technical means by which a
   student might manage and secure his/her own communication.

   By coercing students into a false choice between surrendering their
   privacy or accepting the limitations of a neglected, largely manual
   system, educators and allied service providers gain significant new
   benefits at student expense.  Among these benefits is the creation of
   an otherwise unneeded educational services industry to mediate
   communication between students and transcript recipients --
   communication that, by the most natural operation of the Internet,
   would otherwise be end-to-end.  A second consequence of coerced
   mediation is that the mediators gain unfettered control over school
   records that would otherwise be private and often protected by law.
   A third consequence of coerced mediation is that mediators can
   harvest candid data on student behavior outside the secondary school
   domain.  Even the most basic information about college and employment
   applications, successful or not, individual or in the aggregate, can
   have significant value for secondary school officials, college
   administrators, employers, and general marketing professionals.
   Moreover, although such data is historically private, it is also more
   valuable and legally less well protected than internal secondary
   school records.

   Mediated transcript distribution vitiates student privacy while
   endowing school bureaucrats and their confederates with undeserved
   privilege, but these political concessions are utterly unnecessary to
   automated transcript distribution.  As suggested by Figure 2, the
   political concessions intrinsic to mediated transcript exchange can
   be largely eliminated by the most straightforward automation of the
   traditional transcript process.

   This memo specifies a common format for exchanging secondary school
   academic transcripts via electronic mail.  Because the defined format
   supports digital signature of transcripts by their originator, a
   student cannot fabricate or alter transcript information provided by
   school officials.  Because the described format supports encrypted
   transmission of school transcripts, the distribution of each
   student's information can remain private and under his or her
   control.  Because the format supports asymmetric cryptography, the
   origin and integrity of received transcripts can be verified

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   independently by the recipient; confidential content can be
   independently recovered by an intended recipient while remaining
   protected from unauthorized access.  Because the Internet email
   protocol provides fail-safe delivery, transcripts are reliably
   delivered to their intended recipients, and the sending student is
   directly notified of any exceptions.  No centralized, trusted
   authority is needed to mediate communication between students,
   transcript originators, or transcript recipients.  Thus, a student's
   need for an authoritative record of his education cannot be exploited
   to restrict or monitor his/her free and private interactions with
   colleges, employers, or others.  Students can reclaim control over
   their own personal information and their relationships with
   prospective employers and admissions officers; students can prevent
   surreptitious harvesting of information about their affairs.  Last
   but not least, specialized software is not required by most
   participants in the school transcript exchange protocol: the needs of
   all students and many transcript recipients can be met by existing,
   standards-based, secure email clients.

                                                              +++
                                                             /   \
           /\     Digitally Signed Transcript               /     \
          /  \    Via CD-ROM, Secure Email, etc.           /       \
         / 88 \                                           /         \
        /  88  \                 ---                      | College |
       /        \               (0 0)  +-------------->>  |         |
       | School | +--------->>  ( - )                     +---------+
       |        |                | |    Copies of
       +--------+               |   |     Digitally Signed Transcript
   School Guidance Dept         |   |     Via Secure Email, CD-ROM, etc.
                                 | |
                                 | |  +-------+                 +++
                                 8 8          +------------>>  /   \
                               Student                        /     \
                   Privately and Autonomously                /       \
                   Forwards Digitally Signed Transcript     /         \
                                                            | College |
                                                            |         |
                                                            +---------+

        Figure 2: Traditional Model for Exchanging Secondary School
                                Transcripts

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   The acronym EESST (Email Exchange of Secondary School Transcripts)
   names the format and methods defined here for securely conveying
   student academic records under student control.  Requirements for
   implementors of this specification are expressed here using a keyword
   vocabulary [RFC2119] that is widely understood within the Internet
   community.

2.  Design Motivation

   Implicit in any protocol definition is some assignment of functions
   to the various protocol participants.  When those participants are
   administratively independent one from another, binding assignments of
   protocol function -- which might otherwise seem purely technical
   choices -- are politically significant.  For the sake of
   transparency, this protocol specification explicitly reckons the
   political consequences of its implicit design choices.

   Preparation and delivery of secondary school transcripts most affects
   the interests of individual students.  After all, the process is
   entirely motivated by a student's need to certify his or her personal
   academic achievements as evidence of merit for employment, higher
   education, or other social advancement or reward.  Accordingly,
   individual student needs properly dominate the design of a common
   system for transcript exchange.  Because a secondary school
   transcript certifies a student's personal merit, students need
   transcript documents that are credible to recipients -- for which the
   origin and integrity of transcript content is assured.  Because a
   school transcript records personal information about an individual
   student, student privacy is paramount: control of transcript
   distribution must be closely held by the individual student, and each
   student must be able to protect the confidentiality of his or her
   transcript in transit.

   Communication of transcript content between originator, student, and
   ultimate recipient is most secure only if that communication is end-
   to-end.  While the end-to-end argument [Sal84] is fundamental to the
   design of the Internet, it is also critical to the design of secure
   communication protocols (see Section 6.2 of RFC 1958 [RFC1958]).  In
   contrast, securely communicating student information to a centralized
   (and otherwise uninvolved) third party clearly degrades student
   privacy and increases cost.  Claims to the contrary are at best
   logically absurd and at worst darkly motivated.

   After students, transcript handling must address the interests of
   transcript recipients, which may include college admission officers,
   prospective employers, and scholarship foundations.  Recipients must
   be able to evaluate the origin and integrity of received transcript

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   documents easily and independently.  Secondarily, recipients may
   benefit from mechanical extraction and summary of transcript content
   to support their own internal decision processes.

   Finally, common transcript handling must address the needs of the
   transcript originator -- typically a secondary school guidance
   counselor or other school official.  An originator's legitimate
   interests are reducing the cost of preparing transcript documents and
   meeting any legal or moral obligations to protect student privacy.
   Insofar as the very notion of electronic school transcripts implies
   their automated preparation by computers, dramatic cost reductions
   over traditional manual processes are also implicit.  An originator's
   obligation to protect student privacy is most elegantly and
   inexpensively met by simply not conveying transcript information
   about a particular student to anyone other than that student.

   A protocol by which students must request transcript distributions
   addresses no actual student need but, rather, only the legal needs of
   third parties seeking to intervene in otherwise private
   communications.  The additional effort of formal transcript requests
   is needed only when a mediating third party is involved, because, in
   many jurisdictions, sharing personal information with the third party
   legally requires student consent, and an electronic transcript
   request may be conveniently construed as implicit consent.  Moreover,
   a formal transcript request-response protocol is not needed to
   document delivery of a transcript to its intended recipient.  When
   the student, rather than a third party, directly conveys his/her
   transcript to a chosen recipient, that student has the greatest
   interest in successful communication, can observe any communication
   failures firsthand, and can take corrective action if needed.
   Familiar, standardized protocols provide unambiguous feedback to the
   student about successful transcript delivery.  The SMTP protocol, in
   particular, is defined and implemented to be fail-safe, as described
   in Section 4.1.1.4 of its specification [RFC5321]:

      Receipt of the end of mail data indication requires the server to
      process the stored mail transaction information.  This processing
      consumes the information in the reverse-path buffer, the forward-
      path buffer, and the mail data buffer, and on the completion of
      this command these buffers are cleared.  If the processing is
      successful, the receiver MUST send an OK reply.  If the processing
      fails, the receiver MUST send a failure reply.  The SMTP model
      does not allow for partial failures at this point: either the
      message is accepted by the server for delivery and a positive
      response is returned or it is not accepted and a failure reply is
      returned.  In sending a positive "250 OK" completion reply to the
      end of data indication, the receiver takes full responsibility for

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      the message (see Section 6.1).  Errors that are diagnosed
      subsequently MUST be reported in a mail message, as discussed in
      Section 4.4.

3.  Protocol Overview

   Existing, standardized technology simplifies the process of preparing
   and distributing secondary school transcripts.  Using a computerized
   procedure, a secondary school administrator prepares a digital
   transcript document that records the academic achievements of a
   particular student and presents that document to that student.  Using
   postal delivery, secure email, or other method, the student conveys
   digital copies of the prepared transcript to recipients of his or her
   choice.  Using a computerized procedure, each recipient may
   independently verify that the received transcript has not been forged
   or altered in transit.  Because the received transcript is digital,
   each recipient may use computerized procedures to extract and
   summarize transcript content for local review and processing.

   Preparing and delivering a secondary school transcript entails
   interaction among three kinds of participant -- transcript
   originator, student, and transcript recipient -- each of whom
   performs a distinct functional role.  Interactions between each kind
   of participant are proscribed below.

3.1.  Student and Originator

   A transcript originator assembles and digitally signs academic
   transcripts that document the achievements of individual students in
   a secondary school.  The role of transcript originator is frequently
   filled by the director of a high-school guidance department or other
   secondary school official.  At fixed times throughout the school
   year, using then-current information from a student database, the
   guidance director executes a computer program that, for each relevant
   student, automatically creates an individual transcript report and
   digitally signs that report on the director's behalf.  The format of
   each signed transcript document is defined in Section 5 below.

   The principal responsibilities of a transcript originator are:

   1.  Generate an OpenPGP key pair that can be used to sign school
       transcripts.

   2.  Create and securely store a key revocation certificate for the
       signing key pair for possible future use should it be
       compromised.

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   3.  Publish on the World Wide Web the public component of the
       transcript signing key pair, together with its OpenPGP
       fingerprint.

   4.  Securely store the private component of the signing key pair and
       protect its use with a judiciously chosen passphrase known only
       to the transcript originator.

   5.  Use the signing key pair to create and digitally sign transcripts
       for individual students.

   6.  Present each signed transcript confidentially to the individual
       student to which it pertains.

   Once generated by the transcript originator, each transcript is
   conveyed to the relevant student using any means that protects the
   confidentiality of individual student data.  For example, a digital
   transcript may be written to a CD-ROM storage disk and presented to
   the relevant student when he comes to school.  Alternatively, that
   same CD-ROM could be sealed in an envelope and sent to the student
   via postal delivery.  A student could present a USB flash drive in
   person at the school guidance office, and her digital transcript
   could be copied onto that drive.  A digital school transcript could
   also be presented to the relevant student as a MIME attachment to an
   email message that is encrypted according to the OpenPGP
   specification.  When email is used to convey school transcripts to
   students, formatting such messages as specified in Section 6 below
   will foster security and interoperability.

   After a student receives his/her transcript from its originator, that
   student is solely responsible for conveying that transcript to any
   recipients of his/her choosing, as described in Section 3.2 below.

3.1.1.  Transcript Requests

   For several reasons, how students request generation of an academic
   transcript from their secondary school is a local matter that need
   not and ought not be addressed here.

   First, the volume of requests for transcripts is likely to be
   relatively low, because transcripts can be pre-issued to most
   students (e.g., graduating seniors) who are likely to need them.
   When transcripts are digital and easily duplicated by the student,
   there is no need to generate a new transcript document for each
   desired recipient.  Accordingly, most transcript generation is driven
   not by student requests but rather by content updates arising from
   the predictable passing of marking periods or academic sessions
   throughout the school year.  Thus, explicit requests for transcript

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   generation will be the exception rather than the rule -- from
   students who have lost a previously issued transcript, or students
   leaving the school prior to their graduation.

   Second, a historical motivation for formalizing transcript requests
   has been to satisfy the school's legal obligation to protect student
   privacy.  In many legal jurisdictions, school officials are required
   to seek student authorization for releasing information to a third
   party.  Elaborate procedures for requesting transcripts are attempts
   to codify or automate that authorization process.  However, because,
   under the procedure defined here, each student's information is
   provided only to that student, no authorization for releasing
   information to a third party is required.

   Third, a codified transcript request protocol affords almost no
   benefit beyond enabling third-party processors to assume the role of
   transcript originator and/or distributor.  Students need no formal
   "acknowledgment" of their transcript requests: the transcript itself
   serves that purpose.  Because a digital transcript is easily
   generated by an automated procedure, there is no benefit to returning
   a request acknowledgment rather than the document actually requested.
   The primary goal of this protocol design is to strengthen student
   privacy and agency by eliminating third-party intrusion into what
   would otherwise be private, bilateral interactions between a student
   and his school.  To codify transcript requests is to undercut
   directly that fundamental purpose, while gratuitously restricting
   local interactions between student and school.

   When each student -- rather than a school official or mediating third
   party -- exercises principal control of distributing his or her own
   transcript information, any need for transcript requests is largely
   obviated.  Thus, exchanging and processing such requests is properly
   a local matter and not further addressed here.

3.2.  Student and Recipient

   When a student is asked (e.g., by a college admissions office or
   prospective employer) to provide an official transcript of his or her
   academic achievements, that student may send to the requesting party
   a copy of the digitally signed transcript document that he has
   previously received from his secondary school.  In this context, the
   party requesting that the student send a transcript is called a
   transcript recipient.  Because it is the student who conveys his own
   transcript information, he or she unambiguously controls the set of
   recipients, and neither the secondary school nor any third party is
   responsible for or privy to the identities of his correspondents.
   Similarly, the student is responsible for assuring the privacy of his
   or her personal information as he conveys it to these recipients.

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   The student may convey his transcript to his chosen recipient using
   any mutually agreeable strategy.  For example, he may print a copy of
   his transcript onto a postcard and send it via postal delivery.  This
   strategy does not strongly protect the confidentiality of the
   student's information in transit, nor does this strategy allow the
   recipient to automate verification or other processing of the
   received transcript information.  Sending a paper transcript sealed
   in a postal envelope better protects student confidentiality, but
   similarly restricts the recipient's ability to verify or process
   transcript contents.  By copying his digital transcript onto a CD-ROM
   storage disk and sending that disk, sealed in a postal envelope, via
   surface mail, the recipient can automatically verify and process the
   transcript content, although protection of student confidentiality in
   transit might be stronger.

   Alternatively, a student could send a copy of the digital transcript
   provided by his secondary school merely by attaching the relevant
   computer file to an email message addressed to the recipient.  If the
   student completely trusts the end-to-end email transmission path from
   himself to his intended recipient (e.g., if student and recipient are
   connected by a common, private network), then the student could send
   his transcript in a plaintext email; otherwise, the student SHOULD
   encrypt the email contents to protect his privacy during
   transmission.

   If a student chooses to convey his/her school transcript to a
   transcript recipient via electronic mail, then the principal
   responsibilities of that student are:

   1.  Create a personal email account and associated email address from
       which transmissions of the student's signed school transcript may
       be sent.

   2.  For each potential recipient of the student's signed school
       transcript, discover and record the email address and the public
       OpenPGP key published by that transcript recipient.

   3.  Import the OpenPGP public key for each chosen recipient into the
       local OpenPGP key database.

   4.  Use an email client application that implements the OpenPGP/MIME
       specification [RFC3156] in order to encrypt and transmit a copy
       of the signed school transcript to each chosen recipient.

   Using common formats and methods to convey transcript content
   protects students while also simplifying processing for transcript
   recipients.  The representation of transcripts as specified in
   Section 5 and the use of the transmission formats specified in

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   Section 6 afford privacy and autonomy to students.  By using these
   formats, recipients may independently verify the origin and integrity
   of the transcript information that students provide.  Common
   transcript representation also allows recipients to automate the
   storage, analysis, and review of received transcripts.

   However, a student cannot use the format specified here to convey
   his/her transcript to a chosen recipient unless that recipient is
   prepared to participate in the exchange.  The principal
   responsibilities of a transcript recipient are:

   1.  Generate an OpenPGP key pair that can be used to encrypt student
       transmissions of signed school transcripts to the recipient.

   2.  Create and securely store a key revocation certificate for the
       key pair generated above for possible future use in the event
       that the private key component is compromised.

   3.  Create a (preferably dedicated) email address and mailbox to
       which students may direct transmissions of signed school
       transcripts.

   4.  Publish on the World Wide Web both the dedicated transcript email
       address and the public component of the OpenPGP key pair
       generated above, together with its OpenPGP fingerprint.

   5.  Securely store the private component of the OpenPGP key pair
       generated above and guard its use with a judiciously chosen
       passphrase known only to the transcript recipient.

   6.  Assemble a collection of public OpenPGP keys published by
       legitimate transcript originators.

   7.  Receive and decrypt transcripts transmitted by students.

   8.  Validate the origin and integrity of each received transcript
       using the public OpenPGP key of the relevant transcript
       originator.

   The similarity between the EESST transcript format and generic
   OpenPGP/MIME email messages allows transcript recipients to inspect,
   verify, and extract received school transcripts using existing,
   widely deployed email clients.  By using email client applications
   that support both the MIME and OpenPGP specifications, transcript
   recipients should easily be able to verify the signature of the
   transcript originator and to save the various transcript components
   locally for later review or processing.

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   Using familiar email client applications for receiving and reviewing
   small numbers of received school transcripts does not preclude using
   more automated systems to meet the needs of university admissions
   departments or large employers.  Larger-volume transcript recipients
   might ask students to direct their school transcripts to a particular
   email mailbox.  Transcripts so delivered could be periodically
   received, validated, and otherwise organized by specialized
   application software.  Information in the computational component of
   received transcripts might be incorporated into a candidate database
   to simplify more quantitative evaluations of the applicant pool.

4.  Transcript Content

   The content of a school transcript is represented as a single MIME
   body part whose content type is "multipart/mixed".  This multipart
   representation comprises individual MIME elements that represent (in
   order) prefatory comments from the transcript originator regarding
   the validation and interpretation of the represented transcript
   (described in Section 4.1), a rendering of the relevant school
   transcript suitable for automated processing (described in
   Section 4.2), and a rendering of that same school transcript suitable
   for human review and consideration (described in Section 4.3).
   Figure 3 below schematically presents the MIME structure used to
   represent transcript content; Figure 4 illustrates an example
   representation of transcript content.

   Every representation of transcript content MUST include exactly the
   following set of MIME content headers:

   Content-Type:  This header is defined in Section 5 of the MIME format
        specification [RFC2045] and, when associated with the content of
        a signed school transcript, MUST have the value "multipart/
        mixed".

   Content-Description:  This header is defined in Section 8 of the MIME
        format specification [RFC2045].  Its value provides humans with
        "descriptive information" about the content of the represented
        school transcript.  Notwithstanding the statement in RFC 2045
        that a content description header is optional, this header MUST
        be included in the MIME representation of school transcript
        content.

   MIME-Version:  This header is defined in Section 4 of the MIME format
        specification [RFC2045].  Its value identifies the version of
        the MIME specification to which the associated body part
        conforms.  Currently, the value of this header MUST always be
        "1.0".  Sometimes, the EESST specification can require an
        appearance of the MIME-Version header where it is not otherwise

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RFC 7681              EESST Protocol Specification          October 2015

        strictly required by the MIME format specification.  These
        seemingly gratuitous MIME-Version headers are deliberately
        introduced to help users who may need to apply less-capable
        email clients recursively in order to navigate and display a
        transmitted transcript.

   Eesst-Version:  The value of this header identifies the version of
        the EESST format to which the represented school transcript
        conforms.  Currently, the value of this header MUST always be
        "1.0".

   From:  The value of this header identifies the originator of the
        represented school transcript.  This value names the originating
        official, his organizational title, and includes, enclosed
        within angle brackets, the identity of the OpenPGP key with
        which the represented school transcript has been digitally
        signed.

   Organization:  The value of this header identifies the organization
        or institution to which the originator of the relevant message
        belongs.  Within a school transcript document, the value of this
        header identifies the secondary school that has issued the
        represented school transcript.  By convention, the value of this
        header names the originating institution along with its
        geographical location.

   Subject:  The value of this header provides humans with "descriptive
        information" about the semantic content of the represented
        school transcript.  Inclusion of this header is optional, but,
        if included, its value MUST match that of the "Content-
        Description" header above.  The presence of the "Subject" header
        helps some email reader applications to present school
        transcript transmissions more elegantly.

   Date:  The value of this header identifies the date on which the
        represented school transcript was created, and its format MUST
        be consistent with Section 3.3 of the specification for email
        messages [RFC5322].

   With the exception of the optional "Subject" header, each header
   enumerated above must appear in the MIME body part that represents
   the aggregate content of a school transcript.  No other headers are
   permitted, and the allowed set of headers may appear in any order.
   Example MIME headers for transcript content are presented in
   Figure 4.  In the figure, "PESC" stands for the Postsecondary
   Electronic Standards Council; see Section 4.2 for more information.

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RFC 7681              EESST Protocol Specification          October 2015

         +--------------------------------------------------+
         | TRANSCRIPT CONTENT                               |
         | Content-Type: multipart/mixed                    |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | TRANSCRIPT PREFACE                        | |
         |    | Content-Type: text/plain                  | |
         |    |                                           | |
         |    | Body represents transcript preface        | |
         |    +-------------------------------------------+ |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | COMPUTATIONAL TRANSCRIPT                  | |
         |    | Content-Type: application/xml             | |
         |    |                                           | |
         |    | Body represents PESC XML computational    | |
         |    | transcript                                | |
         |    +-------------------------------------------+ |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | DISPLAY TRANSCRIPT                        | |
         |    | Content-Type: application/pdf             | |
         |    |                                           | |
         |    | Body represents PDF display transcript    | |
         |    +-------------------------------------------+ |
         +--------------------------------------------------+

              Figure 3: MIME Structure of Transcript Content

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   Content-Type: multipart/mixed; boundary="===============BBBBBBBBBB=="
   MIME-Version: 1.0
   Content-Description: Official School Transcript for Hermione Granger
   Subject: Official School Transcript for Hermione Granger
   From: Transcript Authority at Hogwarts School
       <transcript-authority@hogwarts.edu.example>
   Organization: Hogwarts School for Witchcraft and Wizardry
   Eesst-Version: 1.0
   Date: Fri, 22 Mar 2013 09:55:06 -0600

   --===============BBBBBBBBBB==
   Content-Type: text/plain; charset="us-ascii"
   MIME-Version: 1.0
   Content-Transfer-Encoding: 7bit
   Content-Disposition: attachment; filename="preface.txt"
   Content-Description: School Transcript Preface

   To Whom It May Concern:

   This academic transcript describes the accomplishments of an
       ...

   --===============BBBBBBBBBB==
   Content-Type: application/xml
   MIME-Version: 1.0
   Content-Transfer-Encoding: quoted-printable
   Content-Disposition: attachment; filename="transcript.xml"
   Content-Description: School Transcript rendered as PESC XML

   <HSTrn:HighSchoolTranscript=20xmlns:AcRec=3D"urn:org:pesc:sector:Acad
       ...
   cord></Student></HSTrn:HighSchoolTranscript>
   --===============BBBBBBBBBB==
   Content-Type: application/pdf
   MIME-Version: 1.0
   Content-Transfer-Encoding: base64
   Content-Disposition: attachment; filename="transcript.pdf"
   Content-Description: School Transcript rendered as PDF

   JVBERi0xLjMNCiWTjIueIFJlcG9ydExhYiBHZW5lcmF0ZWQgUERGIGRvY3VtZW50IGh0d
       ...
   IC9Sb290IDEwIDAgUg0KIC9TaXplIDE2ID4+DQpzdGFydHhyZWYNCjE3OTIzDQolJUVPR

   --===============BBBBBBBBBB==

                   Figure 4: Example Transcript Content

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4.1.  School Transcript Preface

   A school transcript preface conveys generic comments about a school
   transcript from the originating school official.  This commentary is
   in a form that is widely readable by humans without special
   application tools.  This commentary SHOULD be generic in character,
   providing general information about the preparation and
   interpretation of transcripts issued by the originating institution;
   the transcript preface SHOULD NOT provide information about an
   individual student.  The rhetorical form of a transcript preface is
   sometimes that of a cover letter addressed to a generic transcript
   recipient.  For example, a preface could provide instructions on how
   to verify the digital signature on the transcript or an explanation
   of unusual grading practices at the issuing school.  A school
   transcript preface is represented as a MIME body part whose content
   type is "text/plain".

   When a school transcript is encapsulated for transmission into a
   larger email message, arbitrary text within a transcript preface
   could be accidentally misinterpreted as structural MIME boundaries or
   email headers.  The likelihood of such errors is reduced when preface
   content does not include lines that begin with hyphen (-) characters,
   angle bracket (>) characters, or the word "From."  Although, ideally,
   the transcript preface should be readable by humans without special
   assistance, when these constructs absolutely cannot be avoided within
   preface text, transcript originators SHOULD apply a content transfer
   encoding to the preface that insulates it from misinterpretation by
   intermediary mail transfer agents.

   The representation of a transcript preface SHOULD NOT include any
   header fields beyond those enumerated in the specification for the
   format of MIME message bodies [RFC2045].

4.2.  Computational School Transcript

   A computational school transcript represents the academic
   accomplishments of an individual student in a form suitable for
   automated processing.  Accordingly, the content of a computational
   school transcript is rendered in Extensible Markup Language (XML)
   [XML11] and conveyed as a MIME body part whose content type is
   "application/xml".  The syntax of the data conveyed by a
   computational transcript MUST conform to the XML schema for High
   School Transcripts, Version 1.3.0 [Fun12b], published by the
   Postsecondary Electronic Standards Council (PESC).  This XML schema
   depends in turn upon the Academic Record XML schema, Version 1.7.0
   [Fun12a] and the Core Main XML schema, Version 1.2.0 [Mar06], also

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   published by PESC.  Detailed semantics for the data elements defined
   by these XML schema are defined in the PESC XML implementation guide,
   Version 1.3.0 [Ste12], which also provides usage examples.

   In order to protect student privacy, this specification does not
   require a school transcript to convey any particular student
   information but, rather, defines only a common format for whatever
   student information may be voluntarily exchanged between consenting
   parties.  The scope of the information exchanged is a completely
   local matter, and a transcript originator MAY omit from transcript
   content any information (e.g., a student's social security number,
   the identity and location of a student's parents, a student's race,
   ethnicity, or transgender status) that might be regarded locally as
   sensitive or irrelevant.  Indeed, the requirement that a
   computational transcript conform syntactically to the PESC XML schema
   imposes few, if any, constraints upon the transcript originator's
   choices regarding transcript content.  Figure 5 illustrates a minimal
   set of XML elements that satisfies the syntactic requirements of the
   PESC XML schema.  A computational transcript need convey no more
   information about an individual student than what little is conveyed
   by that figure.

   In order to prevent implicit monitoring and control of student
   interactions with transcript recipients, this specification restricts
   certain uses of the PESC XML schema by transcript originators.  In
   every computational transcript, the "Destination" sub-element of the
   "DataTransmission" element MUST convey no distinguishable information
   and have the particular representation

      "<Destination><Organization/></Destination>"

   that is illustrated in Figure 5.  This requirement assures that a
   student may use self-made copies of a signed transcript document for
   whatever purposes he/she chooses without further consultation with
   issuing school officials.  If the transcript originator is allowed to
   brand particular destinations onto each copy of a student transcript,
   then the originator can easily monitor and (to some degree) control
   the set of college admissions officers, prospective employers, or
   other third parties to whom the student is providing that transcript.
   Transcript recipients MUST reject any transcript whose content in any
   way specifies or restricts the audience, recipient, or distribution
   for that transcript.  Notwithstanding this restriction upon the
   "Destination" element, the "Source" element SHOULD be included within
   a computational transcript and convey information sufficient to
   identify the secondary school or other institution by which the
   relevant transcript is issued.

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   <HSTrn:HighSchoolTranscript
    xmlns:HSTrn="urn:org:pesc:message:HighSchoolTranscript:v1.3.0"
    xmlns:AcRec="urn:org:pesc:sector:AcademicRecord:v1.7.0"
    xmlns:core="urn:org:pesc:core:CoreMain:v1.12.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="urn:org:pesc:message:HighSchoolTranscript:v1.3.0
                        HighSchoolTranscript_v1.3.0.xsd">
     <TransmissionData>
       <DocumentID>X</DocumentID>
       <CreatedDateTime>2011-04-04T09:30:47-05:00</CreatedDateTime>
       <DocumentTypeCode>StudentRequest</DocumentTypeCode>
       <TransmissionType>MutuallyDefined</TransmissionType>
       <Source>
         <Organization/>
       </Source>
       <Destination>
         <Organization/>
       </Destination>
     </TransmissionData>
     <Student>
       <Person>
         <Name/>
       </Person>
       <AcademicRecord/>
     </Student>
   </HSTrn:HighSchoolTranscript>

               Figure 5: A Minimal Set of PESC XML Elements

   Additional restrictions on the use of the PESC XML schema foster
   common, unambiguous interpretation and simplified processing of
   computational transcripts:

   1.  In order to satisfy the minimal syntactic requirements of the
       PESC XML schema, every computational transcript MUST comprise at
       least those XML elements that appear in Figure 5.  Even when a
       transcript originator seeks to convey no information within a
       computational transcript, the computational transcript must be
       included within the relevant transcript content, and its payload
       must have the form illustrated in Figure 5.

   2.  Consistent with the PESC XML schema, any value ascribed to the
       "DocumentID" XML element must be at least one non-whitespace
       character in length.

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   3.  Consistent with the PESC XML schema, any value ascribed to the
       "CreatedDateTime" XML element must have the form of an XML
       "dateTime" value, as defined in Section 3.2.7 of the XML Schema
       Datatype specification [XSD].

   4.  Lest the origin and correct handling for a computational
       transcript be misunderstood, the value ascribed to the
       "DocumentTypeCode" XML element MUST be "StudentRequest".

   5.  Lest the origin and correct handling for a computational
       transcript be misunderstood, the value ascribed to the
       "TransmissionType" XML element MUST be "MutuallyDefined".

   6.  With the exception of those XML elements that appear in Figure 5,
       information that is not provided in a computational transcript
       MUST be represented by entirely omitting the relevant XML data
       element; omitted information MUST NOT be represented by including
       an XML element whose textual value is of zero length or contains
       only whitespace.

   The representation of a computational transcript SHOULD NOT include
   any header fields beyond those enumerated in the specification for
   the format of MIME message bodies [RFC2045].  Although any valid
   content transfer encoding is acceptable for a computational school
   transcript, the "quoted-printable" encoding is preferred.

4.3.  Display School Transcript

   A display school transcript describes the academic accomplishments of
   an individual student in a form suitable for human reading and
   review.  A display school transcript is represented as a MIME body
   part whose content type is "application/pdf" and whose content
   conforms to the Portable Document Format (PDF) specification [PDF17].
   A display school transcript may comprise one or more physical pages.

   In order to reduce the chance that the recipient of a signed school
   transcript could misinterpret its content, the computational
   component (described in Section 4.2 above) and the display component
   (defined here) of each signed school transcript SHOULD convey, to the
   greatest degree possible, identical information about the academic
   accomplishments of the relevant student.

   Nothing in this specification should be construed as requiring
   implementation or use of digital signature features embedded in
   individual PDF documents pursuant to the PDF specification.  Rather,
   the data integrity and origin identity of all components in a school
   transcript --- including the PDF display transcript --- are
   adequately protected by the OpenPGP signature of the transcript

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RFC 7681              EESST Protocol Specification          October 2015

   originator, required by this specification.  Accordingly,
   implementation of PDF-specific signature features is optional and
   largely unwarranted; although transcript recipients MUST accept
   transcripts that include PDF signatures, recipients SHOULD neither
   verify nor depend upon the embedded signatures themselves.

   Transcript originators MUST NOT use the encryption features described
   in the PDF specification to encrypt a display school transcript.  The
   OpenPGP encryption mechanisms specified in Section 6 below adequately
   protect the confidentiality of student information while in transit.
   Thus, separately encrypting the display transcript is redundant.
   Double encryption increases implementation complexity while also
   increasing security risk by requiring additional key distributions.
   Transcript recipients MUST NOT accept or process school transcripts
   for which the PDF display component is independently encrypted.

   Previous work [RFC3778] identifies security considerations arising
   from using the PDF as a MIME media type.  Among these considerations
   is that PDF documents may include executable "scripts" or references
   to external, executable plug-in modules.  Including arbitrary
   executable programs (or references thereto) in a PDF transcript
   document poses a security risk to transcript recipients.  Digitally
   signing PDF documents (or even the transcripts that contain them)
   does not help transcript recipients to evaluate the safety of
   executing any embedded programs or plug-ins.  The primary purpose of
   using PDF is to present static transcript information in an
   attractive format for human review.  Because this limited purpose is
   admirably served without embedding executable elements in PDF files,
   any risk posed by their inclusion is unwarranted.  Accordingly,
   transcript originators MUST NOT include in a PDF display transcript
   any executable scripts or external plug-in references.  In order to
   preclude execution of untrusted programs on their local system,
   transcript recipients SHOULD use only trusted tools to process and
   view display transcripts.

   The representation of a display school transcript SHOULD NOT include
   any header fields beyond those enumerated in the specification for
   the format of MIME message bodies [RFC2045].

5.  Signed School Transcript

   A signed school transcript is a MIME body part whose form corresponds
   to that of a signed OpenPGP/MIME message, as described in section 5
   of the OpenPGP/MIME specification [RFC3156].  Accordingly, the MIME
   content type of a signed school transcript is "multipart/signed", and
   its form reflects the traditional use of multipart MIME structures to
   secure email communication [RFC1847].  Thus, the body of a signed
   school transcript comprises exactly two parts, as illustrated in

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   Figure 6.  The first part of the signed transcript body conveys the
   transcript content, in MIME canonical format, including an
   appropriate set of MIME content headers.  The form and interpretation
   of the transcript content is described in Section 4 above.  The
   second part of the signed transcript body is the school transcript
   signature.  The signature part represents the OpenPGP digital
   signature of the transcript originator as it has been applied to the
   transcript content conveyed by the first part of the signed
   transcript.  The transcript signature is assigned the content type
   "application/pgp-signature".  Transcript recipients MUST reject
   transcripts that are not validly signed pursuant to the specification
   for OpenPGP signatures [RFC3156].

         +--------------------------------------------------+
         | SIGNED TRANSCRIPT                                |
         | Content-Type: multipart/signed                   |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | TRANSCRIPT CONTENT                        | |
         |    | Content-Type: multipart/mixed             | |
         |    |                                           | |
         |    | Body represents transcript content        | |
         |    +-------------------------------------------+ |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | TRANSCRIPT SIGNATURE                      | |
         |    | Content-Type: application/pgp-signature   | |
         |    |                                           | |
         |    | Body represents OpenPGP signature over    | |
         |    | transcript content                        | |
         |    +-------------------------------------------+ |
         +--------------------------------------------------+

               Figure 6: MIME Structure of Signed Transcript

   With the sole exception of the "Content-Type" header, the MIME
   content headers for each signed school transcript MUST correspond
   exactly to those for the embedded transcript content, as described
   above in Section 4.  For a signed school transcript, the value of the
   "Content-Type" header MUST be "multipart/signed", its parameters MUST
   conform to those described in Section 5 of the MIME/OpenPGP
   specification [RFC3156], and the value of the "boundary" parameter
   shall, of course, differ from all other boundary parameter values
   within the same message.  Figure 7 presents example headers for a
   signed school transcript.  Although the allowed headers may appear in
   any order, transcript recipients MUST reject signed transcripts for
   which the set of included headers differs from the set of headers
   associated with the embedded transcript content.

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   Content-Type: multipart/signed;
       protocol="application/pgp-signature";
       micalg="pgp-sha256";
       boundary="===============AAAAAAAAAA=="
   MIME-Version: 1.0
   Content-Description: Official School Transcript for Hermione Granger
   Subject: Official School Transcript for Hermione Granger
   From: Transcript Authority at Hogwarts School
       <transcript-authority@hogwarts.edu.example>
   Organization: Hogwarts School for Witchcraft and Wizardry
   Eesst-Version: 1.0
   Date: Fri, 22 Mar 2013 09:55:06 -0600

   --===============AAAAAAAAAA==
   Content-Type: multipart/mixed; boundary="===============BBBBBBBBBB=="
   MIME-Version: 1.0
   Content-Description: Official School Transcript for Hermione Granger
       ...  Transcript Content as illustrated in Figure 4  ...

   --===============BBBBBBBBBB==--

   --===============AAAAAAAAAA==
   Content-Type: application/pgp-signature; name="signature.asc"
   MIME-Version: 1.0
   Content-Description: OpenPGP signature
   Content-Disposition: attachment; filename="signature.asc"

   -----BEGIN PGP SIGNATURE-----
   Version: GnuPG v1.4.10 (GNU/Linux)

   iQEcBAABAgAGBQJRmkkLAAoJEBzD54azv/d4j4gH/1Aj8poEHLsEhxdv26H76URX
       ...
   8/SQRZGUGUC0xSej5uQMVI59Yriy3dedlzib7EadK6fnz70SsEzUcQy5lHFkNNA=
   =8QLW
   -----END PGP SIGNATURE-----

   --===============AAAAAAAAAA==--

                Figure 7: Example Signed School Transcript

   The "Eesst-Version" header serves a crucial if non-obvious purpose
   for protocol implementors.  The presence of this header unambiguously
   distinguishes a signed school transcript from elements of an
   enveloping email message by which that transcript may be conveyed.

   For good reason, the format defined here for signed school
   transcripts intentionally shares many characteristics with the
   standard format for OpenPGP/MIME messages [RFC3156].  This similarity

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   not only admits some code reuse within recipient implementations,
   but, most importantly, also allows transcript recipients to inspect,
   verify, and extract received school transcripts using existing,
   widely deployed email clients.

   However, the formal similarity between signed school transcripts and
   generic signed messages can complicate recipient implementations of
   the transcript exchange protocol, because every signed body part must
   be fully evaluated to determine its status.  When a signed school
   transcript is conveyed to its recipient enclosed within a signed
   OpenPGP email message, both transcript and conveying message share
   the common MIME type "multipart/signed".  Moreover, both signed
   transcript and its conveying message share a common, high-level
   structure comprising exactly two MIME body parts, independently
   representing the signed content and the applied digital signature.
   When a "multipart/signed" MIME body part is encountered as part of a
   received email message, should that body part be construed as a
   proper signed school transcript, a signed email message by which a
   school transcript is conveyed, ill-formed school transcript, or
   something else altogether?  Without additional information,
   unambiguously answering these questions requires that every signed
   body part be fully verified, parsed, validated, and checked, because,
   absent additional information, a receiving implementation cannot know
   what tests need to be applied.

   Thus, the "Eesst-Version" header serves at least two important
   functions.  Most obviously, this header identifies what version of
   the EESST format has been applied in preparation of the relevant
   transcript.  Although, currently, the only acceptable version of the
   EESST format is 1.0, to deny even the possibility of future protocol
   evolution is to deny the lessons of history.  Less obviously, the
   "Eesst-Version" header allows simple, unambiguous detection of signed
   school transcripts while still allowing transcript recipients to
   validate and review school transcripts using familiar, widely
   available email clients.  For these reasons, the "Eesst-Version"
   header MUST be included in signed school transcripts and their
   content component, but, in order to most fully realize its value as
   syntactic disambiguator, the "Eesst-Version" header MUST NOT appear
   anywhere else.

6.  Transcript Transmission

   Provided that the transcript originator is prohibited from disclosing
   personal information without student consent, use of the EESST
   protocol empowers each student to limit sharing of his or her own
   school transcript to recipients chosen by that student.  The design
   of the protocol not only protects the confidentiality of transcript
   content in transit but also increases the cost of surveillance by the

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   school or other interested parties of the student's interactions with
   colleges, prospective employers, or other third parties.

   A student may convey his signed school transcript to his chosen
   recipient using any medium or technology that is agreeable to them
   both.  For example, a student may copy his signed digital transcript
   onto a CD-ROM storage disk and send that physical medium to his
   intended recipient via a postal mail service.  However, because email
   will frequently be the most convenient means for students to
   distribute their transcripts, this specification defines a common
   email format by which each student may privately convey his/her
   signed school transcript to each recipient.  A common form for
   transcript transmission simplifies implementations of the transcript
   exchange protocol and fosters their interoperability.  A common
   format allows high-volume transcript recipients to automate
   decryption and validation of received transcripts as well as their
   preparation for subsequent review and analysis.  A common format that
   derives from existing email standards allows low-volume transcript
   recipients to use popular email client software to receive, decrypt,
   validate, and review transcripts.

   When a student conveys his transcript to a recipient via email, that
   student's confidential transcript information is vulnerable to
   interception and disclosure.  In order to mitigate this threat, this
   specification generally requires that the conveying email message be
   encrypted as described in the OpenPGP standard [RFC3156].  Every
   transcript recipient MUST be prepared to accept all transcript
   transmissions that are encrypted as described in any of the sections
   below.  A student SHOULD use either the encrypted transmission format
   (Section 6.1) or the encrypted and signed transmission format
   (Section 6.2), if he or she independently trusts that the
   transmitting computer will correctly transmit his or her transcript
   according to the OpenPGP/MIME specification without disclosing its
   plaintext content.  Otherwise, students MAY use the encrypted file
   transmission format (Section 6.3) or traditional inline transmission
   format (Section 6.4) below.  These latter formats simplify using a
   more trusted computer to encrypt a student's transcript and later
   transferring its encrypted form to a less trusted computer for
   transmission to the chosen recipient.

   Because transcript transmissions must be encrypted in order to assure
   student privacy, every potential transcript recipient MUST generate
   an OpenPGP key pair and publish its public component for use by
   students in the preparation of those transmissions.  The public key
   for each transcript recipient should be published (together with its
   OpenPGP fingerprint) on the web page for that recipient or in the
   global OpenPGP key database.  To protect the privacy of personal
   information transmitted to each chosen recipient, a student need only

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RFC 7681              EESST Protocol Specification          October 2015

   retrieve the published key for that recipient and use it to encrypt
   the transcript transmission.

   With some effort, however, an attacker could, by masquerading as a
   legitimate transcript recipient, perhaps trick a student into
   transmitting private information to the attacker, encrypted in a key
   that is known to the attacker.  In order to protect student privacy
   in the face of such attacks, a transcript recipient should resist
   successful forgery of his/her OpenPGP identity by asking other
   trustworthy individuals (e.g., respected colleagues or institutional
   officers) to certify that identity.  An OpenPGP identity is certified
   by affixing another's digital signature to the associated OpenPGP key
   (see Section 12 of the OpenPGP message format specification [RFC4880]
   and Section 3 in the GNU Privacy Handbook [GPH]).  Those who sign a
   recipient's public key are implicitly vouching for the association
   between that key and the true identity of the recipient.  Consistent
   with the view that the student bears primary responsibility for the
   privacy of his/her transcript information, the student is ultimately
   responsible for evaluating the authenticity of public keys that he/
   she uses to encrypt that information while in transit.  Adding
   certifying signatures to a recipient's key reduces the chance that a
   student could be deceived by an imposter.

   In order to maximize student privacy and autonomy, the operation of
   this protocol sharply separates the function of transcript creation
   from the function of transcript transmission.  The former function is
   assigned exclusively to the issuing secondary school (the transcript
   originator), while the latter function is assigned exclusively to the
   individual student.  Participants in the protocol must behave so as
   to preserve the privacy afforded by this separation.  A transcript
   originator MUST NOT transmit, share, or distribute a school
   transcript or any component thereof to any party other than the
   individual student to whom it pertains.  A transcript recipient MUST
   reject any transcript that seems to have been transmitted by or on
   behalf of anyone but the student.  Although non-student transcript
   transmission can be difficult to detect reliably, certain
   transmission characteristics unambiguously suggest abuse of student
   prerogatives.  Accordingly, all recipient implementations MUST detect
   and reject transcript transmissions with any of the following
   characteristics:

   o  A transcript recipient MUST reject any transcript that is
      delivered in the same email message or on the same physical
      storage medium as any other.

   o  A transcript recipient MUST reject any transcript for which the
      transcript originator and the sender of the transcript
      transmission are identical.

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RFC 7681              EESST Protocol Specification          October 2015

   o  A transcript recipient MUST reject any transcript for which the
      transcript originator (who signs that transcript) and the signer
      of the transcript transmission are identical.

   o  A transcript recipient MUST reject any transcript for which the
      received transcript transmission is addressed to multiple
      recipients.

6.1.  Encrypted Format

   In the encrypted transmission format, the signed school transcript is
   conveyed to a single recipient as a MIME attachment to an OpenPGP
   encrypted email message.  Consistent with Section 4 of the OpenPGP/
   MIME specification [RFC3156], the transmission email message must
   have MIME content type "multipart/encrypted", and, as illustrated in
   Figure 8, the body of the message must comprise exactly two parts.
   The first body part must have MIME content type "application/
   pgp-encrypted", and its content must include only the literal value
   "Version: 1" on a line by itself.  The second body part must have
   MIME content type "application/octet-stream".  Its content is the
   result of applying the OpenPGP encryption algorithm to the MIME
   canonical representation of the relevant signed school transcript.

         +--------------------------------------------------+
         | ENCRYPTED TRANSCRIPT TRANSMISSION                |
         | Content-Type: multipart/encrypted                |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | GRATUITOUS TEXTUAL PREAMBLE               | |
         |    | Content-Type: application/pgp-encrypted   | |
         |    |                                           | |
         |    | Body is literal "Version: 1"              | |
         |    +-------------------------------------------+ |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | ENCRYPTED SIGNED TRANSCRIPT               | |
         |    | Content-Type: application/octet-stream    | |
         |    |                                           | |
         |    | Body represents OpenPGP encryption of     | |
         |    | signed school transcript                  | |
         |    +-------------------------------------------+ |
         +--------------------------------------------------+

       Figure 8: MIME Structure of Encrypted Transcript Transmission

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RFC 7681              EESST Protocol Specification          October 2015

6.2.  Encrypted and Signed Format

   In the encrypted and signed transmission format, the signed school
   transcript is conveyed to a single recipient as an attachment to an
   OpenPGP encrypted and signed email message.  Consistent with
   Section 6.1 of the OpenPGP/MIME specification [RFC3156], preparation
   of a message in this format is a two-stage process.  During this
   process, the transcript transmission is, first, digitally signed by
   the transmitting student and, second, encrypted to protect student
   information from disclosure to anyone but the lone recipient.

         +--------------------------------------------------+
         | SIGNED TRANSCRIPT TRANSMISSION                   |
         | Content-Type: multipart/signed                   |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | SIGNED TRANSMISSION CONTENT               | |
         |    | Content-Type: multipart/signed            | |
         |    |                                           | |
         |    | Body is signed school transcript          | |
         |    +-------------------------------------------+ |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | TRANSMISSION SIGNATURE                    | |
         |    | Content-Type: application/pgp-signature   | |
         |    |                                           | |
         |    | Body is OpenPGP signature over signed     | |
         |    | transmission content                      | |
         |    +-------------------------------------------+ |
         +--------------------------------------------------+

        Figure 9: MIME Structure of Signed Transcript Transmission

   The first stage of preparing an encrypted and signed transcript
   transmission is applying the student's signature to the transmission
   content.  As illustrated in Figure 9, the resulting MIME body part
   has content type "multipart/signed" and comprises exactly two parts.
   The first part is the signed transmission content and corresponds to
   the signed school transcript in its entirety, whose structure is
   illustrated in Figure 6.  The second part is the transmission
   signature.  Its MIME content type is "application/pgp-signature", and
   its content is the result of applying the OpenPGP signature
   algorithm, using the student's private key, to the transmission
   content, the canonical representation of the signed school
   transcript, which is already signed by the transcript originator.

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RFC 7681              EESST Protocol Specification          October 2015

         +--------------------------------------------------+
         | ENCRYPTED TRANSCRIPT TRANSMISSION                |
         | Content-Type: multipart/encrypted                |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | GRATUITOUS TEXTUAL PREAMBLE               | |
         |    | Content-Type: application/pgp-encrypted   | |
         |    |                                           | |
         |    | Body is literal "Version: 1"              | |
         |    +-------------------------------------------+ |
         |                                                  |
         |    +-------------------------------------------+ |
         |    | ENCRYPTED SIGNED TRANSCRIPT               | |
         |    | Content-Type: application/octet-stream    | |
         |    |                                           | |
         |    | Body represents OpenPGP encryption of     | |
         |    | signed transcript transmission            | |
         |    +-------------------------------------------+ |
         +--------------------------------------------------+

      Figure 10: MIME Structure of Encrypted Transcript Transmission

   The second stage of preparing an encrypted and signed transcript
   transmission is wrapping the result of the first stage into an
   OpenPGP encrypted message, protecting student information from
   disclosure to anyone but the lone recipient.  As illustrated in
   Figure 10, the encrypted transcript transmission has the form
   proscribed in Section 6.1 of the OpenPGP/MIME specification.  The
   MIME content type is "multipart/encrypted" and the result comprises
   exactly two body parts.  The first body part must have MIME content
   type "application/pgp-encrypted", and its content must include only
   the literal value "Version: 1" on a line by itself.  The second body
   part must have MIME content type "application/octet-stream".  Its
   content is the result of applying the OpenPGP encryption algorithm to
   the MIME canonical representation of the relevant signed transcript
   transmission, which was produced during the first stage of the two-
   stage process.

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RFC 7681              EESST Protocol Specification          October 2015

6.3.  Encrypted File Format

   Privacy protections afforded by the EESST protocol depend upon the
   assumption that the computer used by the student to transmit his or
   her school transcript reliably executes the required EESST protocol
   operations without disclosing confidential information.  In
   particular, the transmitting computer is assumed to prevent any
   access to the plaintext form of a school transcript by anyone but the
   student.  The hardware and software of the transmitting computer is
   assumed to be free of any flaws that could weaken the encryption
   applied to his or her transcript.  The transmitting computer is also
   assumed to send the transcript reliably and directly to each chosen
   recipient without reporting to any third party either the fact of
   this transmission or the identity of the recipient.  Validating these
   assumptions can be especially problematic when the student does not
   unilaterally own and control the transmitting computer.

   Sometimes the computer from which a student must transmit his or her
   transcript cannot reasonably be trusted.  Indeed, some email client
   implementations manifestly do not permit students to compose a secure
   email message without sharing private information with either their
   email provider, system administrator, or other third party.  Web-
   based email clients are perhaps the most obvious and widespread
   example of intrinsically insecure email platforms: neither
   cryptographic keys nor plaintext message content can be safely stored
   or processed on such systems.  Another example of intrinsically
   insecure platforms are computers and email servers provided for
   student use by schools, to which, as a practical matter, school
   administrators and technical staff enjoy unrestricted access.

   A student may use the encrypted file transmission format when the
   computer that he or she must use to transmit his or her transcript
   cannot be trusted to perform the necessary encryption correctly or
   without disclosing the plaintext transcript.  This format simplifies
   using a more trusted computer to encrypt a student's transcript and
   later transferring its encrypted form to a less trusted computer for
   transmission to the chosen recipient.

   For example, the student may use an implementation of the OpenPGP
   cryptographic algorithms on a trusted computer to encrypt the
   plaintext version of his or her signed school transcript, received
   from the transcript originator.  The key used for this encryption is
   the public OpenPGP key of the intended transcript recipient.  The
   binary file that results from this encryption is then transferred
   (e.g., via a USB flash drive or networked file transfer protocol) to
   a less trusted computer for email transmission to the chosen
   recipient.  On this less trusted computer, the student invokes an
   email client application to compose and send a plaintext email

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RFC 7681              EESST Protocol Specification          October 2015

   message (for example, see Figure 11) to the recipient that is
   formatted according to the MIME specification [RFC2045].  The binary
   file containing the encrypted version of the student transcript is
   included in the message as a MIME attachment whose content type is
   "application/octet-stream".

   When the email message is received by the transcript recipient, the
   MIME attachment containing the encrypted school transcript may be
   detached and saved as a binary file on the local disk.  A local
   OpenPGP implementation is invoked to decrypt the saved file using the
   private OpenPGP encryption key generated by the transcript recipient.
   The process of detaching and decrypting the attached school
   transcript may be automated by large-volume transcript recipients.

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RFC 7681              EESST Protocol Specification          October 2015

  Message-ID: <55650A7F.7090800@granger-dentistry.com.example>
  Date: Tue, 26 May 2015 20:06:23 -0400
  From: Hermione Granger <hermione@granger-dentistry.com.example>
  MIME-Version: 1.0
  To: Dean Vernon Wormer <transcript-receiver@faber.edu.example>
  Subject: Transmission of School Transcript
  Content-Type: multipart/mixed;
   boundary="------------010307000006020005010307"

  This is a multi-part message in MIME format.
  --------------010307000006020005010307
  Content-Type: text/plain; charset=utf-8
  Content-Transfer-Encoding: 7bit

  Dear Dean Wormer:

  Please find attached my high school transcript, encrypted in the
  public encryption key published by Faber College for transcript
  transmission.  I stored the plaintext signed transcript that I
  received from my high school on my own secure computer under the
  filename TrnGranger.eml and encrypted its contents for transmission
  by invoking the following command:

  gpg --encrypt --recipient transcript-receiver@faber.edu TrnGranger.eml

  The resulting encrypted file, TrnGranger.eml.gpg, is attached to
  this email message.  Save that file to the disk on your local
  computer and decrypt the transcript by invoking the command:

  gpg --output TrnGranger.eml --decrypt TrnGranger.eml.gpg

  Sincerely,
  Hermione Granger

  --------------010307000006020005010307
  Content-Type: application/octet-stream; name="TrnGranger.eml.gpg"
  Content-Transfer-Encoding: base64
  Content-Disposition: attachment; filename="TrnGranger.eml.gpg"

  hQEMA4Fu2Js7ulkaAQf/aeiLeoy9L+YddGr0HieHd3KH3wiqLnaImsBaLfboGx+EdTIRn
      ...
  cSJlVDOZKj6nPULT5zqYsfTEHPf+5escZab4J2Rkt/w1BhNDtulNJrbv6q2lk3xBzlt+Z
  kQ==
  --------------010307000006020005010307--

             Figure 11: Encrypted File Transcript Transmission

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RFC 7681              EESST Protocol Specification          October 2015

6.4.  Traditional Inline Format

   A student may use the traditional inline transmission format when the
   computer that he or she must use to transmit his or her transcript
   cannot be trusted to perform the necessary encryption correctly or
   without disclosing the plaintext transcript.  In common with the
   encrypted file transmission format described above (Section 6.3), the
   traditional inline format simplifies using a more trusted computer to
   encrypt a student's transcript and later transferring its encrypted
   form to a less trusted computer for transmission to the chosen
   recipient.

   The traditional inline format allows a student to use an
   implementation of the OpenPGP cryptographic algorithms on a trusted
   computer to encrypt the plaintext version of his or her signed school
   transcript, received from the transcript originator.  The key used
   for this encryption is the public OpenPGP key of the intended
   transcript recipient.  The encrypted transcript is represented as an
   ASCII-armored text file that is then transferred (e.g., via a USB
   flash drive or networked file transfer protocol) to a less trusted
   computer for email transmission to the chosen recipient.  On this
   less trusted computer, the student invokes an email client
   application to compose and send a plaintext email message to the
   recipient.  The content of the ASCII-armored file containing the
   encrypted version of the student transcript is pasted (or otherwise
   inserted) into the new email message as the sole content of its body.

   A traditional inline transcript transmission has the form of a simple
   email message (in the Internet Message Format [RFC5322]) whose body
   is exclusively and entirely the encrypted form of the signed school
   transcript being transmitted.  Representation of the included
   transcript MUST conform to the OpenPGP Message Format specification
   [RFC4880] for the ASCII-armored encoding of the OpenPGP encryption of
   the canonical MIME representation of the relevant signed school
   transcript.  An example inline transcript transmission is illustrated
   in Figure 12.

   When the email message is received by the transcript recipient, a
   local OpenPGP implementation is invoked to extract and decrypt the
   inline representation of the encrypted school transcript, using the
   private OpenPGP encryption key generated by the transcript recipient.
   The process of extracting and decrypting the transmitted school
   transcript may be automated by large-volume transcript recipients.

   While the traditional inline format is an acceptable method of secure
   transcript transmission, it is probably best suited to students who
   lack ready alternatives.  Because inline representation of OpenPGP
   messages can sometimes be incompatible with other email features and

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RFC 7681              EESST Protocol Specification          October 2015

   conventions, the encrypted file format may be a better alternative
   for transcript transmissions when the transmitting computer cannot be
   trusted.  A brief essay by Josefsson [Jos07] identifies multiple
   difficulties that can arise from use of inline OpenPGP, although none
   is strictly relevant to a correctly formed EESST transcript
   transmission.  Accordingly, the traditional inline format may be used
   when needed but only with full consideration of its potential
   limitations on interoperability.

   Return-Path: <hermione@granger-dentistry.com.example>
   Delivered-To: transcript-receiver@faber.edu.example
   MIME-Version: 1.0
   Content-Disposition: inline
   Content-Type: text/plain
   Date: Wed, 3 Jul 2013 12:40:01 -0400
   From: Hermione Granger <hermione@granger-dentistry.com.example>
   To: Transcript Receiver at Faber College
      <transcript-receiver@faber.edu.example>
   Subject: Encrypted Inline Transmission of School Transcript
   X-Mailer: smtp-cli 3.3, see http://smtp-cli.logix.cz
   Content-Transfer-Encoding: 8bit
   Message-ID: <1372869801.14441.1.camel@hermione>

   -----BEGIN PGP MESSAGE-----
   Version: GnuPG v1.4.10 (GNU/Linux)

   hQEMA4Fu2Js7ulkaAQf9Fm4+75kE6gQ1T8pjzf4GJhtBqxTTh2AaGtKZkZy9TW8h
   zsbSNzZuTVf8QvJRSfk0mZywRG42dilf4Zoygpj3xJgKf7JlCEXnY5m4Luq5hvnW
       ...
   hKgY5Kye/cu/4qwYdFOiljkMR1tv1Avh37OmmcMOZ6Hy9gbdrgQzHsPVWLDQNUYy
   jxUAN8thZooRj/jHgq23EZaNyKxD
   =Dga7
   -----END PGP MESSAGE-----

       Figure 12: Traditional Inline Signed Transcript Transmission

7.  Security Considerations

   The security of the EESST protocol depends upon the security of the
   OpenPGP protocols on which it is based.  Although the cryptographic
   algorithms included in OpenPGP are among the strongest used in any
   known protocol, the integrity, authenticity, and confidentiality of
   conveyed student information is not assured unless EESST protocol
   implementors and users faithfully observe all requirements and
   recommendations of the relevant specifications ([RFC4880], [RFC3156],
   and [RFC4270]).  In particular, the SHA-256 digest algorithm and RSA
   key lengths of at least 2048 bits MUST be used.  Happily, these are
   supported by all major OpenPGP implementations.

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RFC 7681              EESST Protocol Specification          October 2015

7.1.  Originator Private Key

   The authority and integrity of generated school transcripts depend on
   the continued secrecy of the private cryptographic key by which those
   transcripts are signed.  For greatest security, the guidance director
   should be physically present when and where the computer program is
   invoked to generate and sign the transcripts.

   When an OpenPGP public-private key pair is generated for use by a
   transcript originator, a key revocation certificate should also be
   generated and securely stored.  In the event that the generated key
   pair is compromised, the stored revocation certificate may be used to
   notify others to reject subsequent uses of that key.

7.2.  Originator Public Key

   The public cryptographic key for each transcript originator should be
   published (together with its OpenPGP fingerprint) on the web page for
   the originating institution and/or in the global OpenPGP key
   database.  Instructions for retrieving and validating the
   originator's public key should be included in the preface of all
   issued transcripts.

   An association of school guidance professionals may wish to publish
   an online collection of OpenPGP public keys submitted by their
   members.  A college admissions officer (or other high-volume
   transcript recipient) could then download and import this key
   collection into a local key database for use in verifying received
   transcripts.

7.3.  Originator Certification

   In order to reduce the chance that an imposter might successfully
   masquerade as a particular transcript originator and substitute a
   false key for the authentic one, the identification of each
   transcript originator with a particular OpenPGP key should be
   certified by other well-known, trustworthy officials.  To this end,
   the public key for a transcript originator should be signed by other
   officials of the originating secondary school, e.g., its principal,
   senior faculty, or local school board members.  The OpenPGP public
   keys of these certifying officials should be published.

7.4.  Recipient Public Key

   The public cryptographic key for each transcript recipient should be
   published (together with its OpenPGP fingerprint) on the web page for
   the receiving institution and/or in the global OpenPGP key database.

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RFC 7681              EESST Protocol Specification          October 2015

7.5.  Secure Clients

   The cryptographic operations upon which the security properties of
   this protocol depend must be performed in private by the relevant
   stakeholder.  The confidentiality of a student's personal transcript
   information cannot be sustained if others enjoy unauthorized access
   to that content during the process of encryption.  The integrity of
   an originator's signature on each transcript cannot be assured if
   others can learn the originator's secret key by observing the
   signature process.  The confidentiality of personal information sent
   by many students to a particular transcript recipient cannot be
   assured if others can learn that recipient's secret key by observing
   the decryption of received transcripts.  Therefore, every stakeholder
   should perform the cryptographic operations proscribed here only when
   present at a physically isolated computer that is entirely controlled
   by that stakeholder and that locally stores all keys and confidential
   information.  Using "thin clients" or web-based computing to perform
   sensitive cryptographic operations forfeits whatever protections this
   protocol might have otherwise afforded.

7.6.  Automatic Replies

   Recipient implementations should not reply automatically or routinely
   to received transcript transmissions.  Such replies could provide
   valuable feedback to an attacker, especially if they can be elicited
   at will.

8.  IANA Considerations

   The EESST exchange format is compatible with and entails no
   alterations to existing email standards.  Indeed, the syntactic
   similarity between the exchange format and standardized email message
   formats empowers users to apply widely deployed email tools to
   verify, interpret, or otherwise manipulate secondary school
   transcripts.

   In the hope of preventing any incompatibilities that could arise from
   future standards evolution or changes in common usage, this section
   describes the registration of two message header fields that are used
   in the EESST exchange format but currently lack any formal definition
   in existing standards.  Consistent with registration procedures
   defined in RFC 3864 [RFC3864], the subsections below describe
   additions to the "Message Headers" registry maintained by the
   Internet Assigned Numbers Authority.

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RFC 7681              EESST Protocol Specification          October 2015

8.1.  Registration of Eesst-Version Header

   The "Eesst-Version" message header field is completely internal to
   the EESST transcript format, and, indeed, explicitly precluded from
   appearing within an enveloping email message (see Section 5).
   Registration has been completed in order to discourage its use in
   other contexts.

   Header field name: Eesst-Version

   Applicable protocol: mail

   Status: provisional

   Author/Change controller:  James R. Davin
                              info@eesst.org
                              http://www.eesst.org

   Specification document(s): RFC 7681

   Related information:
      The value of this header field identifies the version of the
      EESST exchange format to which the represented school transcript
      conforms.  This header may appear only within EESST school
      transcripts.

8.2.  Registration of Organization Header

   The EESST exchange format entails use of the "Organization" message
   header field to identify the originating institution for a student
   transcript.  A header field of this name and semantics is already
   defined for use within network news articles (see [RFC5536]).
   Moreover, the "Organization" header field also frequently appears in
   electronic mail messages, although, perhaps surprisingly, it
   currently lacks any explicit, written definition in that context.
   This registration publicly documents ongoing use of this header field
   and may discourage incompatible uses in future.

   Header field name: Organization

   Applicable protocol: mail

   Status: informational

   Author/Change controller:  James R. Davin
                              info@eesst.org
                              http://www.eesst.org

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RFC 7681              EESST Protocol Specification          October 2015

   Specification document(s): RFC 7681

   Related information:
      The value of this header field identifies the organization or
      institution to which the originator of the relevant message
      belongs.

      Note: this field is quite distinct from the mail address fields
      MTS.OrganizationName and MTS.OrganizationalUnitNames used in
      X.400 mail.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

9.2.  Informative References

   [Fun12a]   Funck, J., "XML Schema for the PESC Format for Academic
              Record Data Elements, Version 1.7.0", June 2012,
              <http://www.pesc.org/library/docs/standards/
              High%20School%20Transcript/AcademicRecord_v1.7.0.xsd>.

   [Fun12b]   Funck, J., "XML Schema for the PESC Format for High School
              Transcripts, Version 1.3.0", June 2012,
              <http://www.pesc.org/library/docs/standards/
              High%20School%20Transcript/
              HighSchoolTranscript_v1.3.0.xsd>.

   [GPH]      Ashley, J., "The GNU Privacy Handbook", 1999,
              <https://www.gnupg.org/gph/en/manual.pdf>.

   [Jos07]    Josefsson, J., "Inline OpenPGP Considered Harmful", April
              2007, <http://josefsson.org/
              inline-openpgp-considered-harmful.html>.

   [Mar06]    Marton, B., "XML Schema for the PESC Format for Core Main
              Data Elements, Version 1.2.0", February 2006,
              <http://www.pesc.org/library/docs/standards/
              High%20School%20Transcript/CoreMain_v1.2.0.xml>.

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RFC 7681              EESST Protocol Specification          October 2015

   [PDF17]    Adobe Systems, Inc., "Document Management - Portable
              Document Format - Part 1: PDF 1.7, First Edition", July
              2008, <http://wwwimages.adobe.com/www.adobe.com/content/
              dam/Adobe/en/devnet/pdf/pdfs/PDF32000_2008.pdf>.

   [RFC1847]  Galvin, J., Murphy, S., Crocker, S., and N. Freed,
              "Security Multiparts for MIME: Multipart/Signed and
              Multipart/Encrypted", RFC 1847, DOI 10.17487/RFC1847,
              October 1995, <http://www.rfc-editor.org/info/rfc1847>.

   [RFC1958]  Carpenter, B., Ed., "Architectural Principles of the
              Internet", RFC 1958, DOI 10.17487/RFC1958, June 1996,
              <http://www.rfc-editor.org/info/rfc1958>.

   [RFC2045]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part One: Format of Internet Message
              Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996,
              <http://www.rfc-editor.org/info/rfc2045>.

   [RFC3156]  Elkins, M., Del Torto, D., Levien, R., and T. Roessler,
              "MIME Security with OpenPGP", RFC 3156,
              DOI 10.17487/RFC3156, August 2001,
              <http://www.rfc-editor.org/info/rfc3156>.

   [RFC3778]  Taft, E., Pravetz, J., Zilles, S., and L. Masinter, "The
              application/pdf Media Type", RFC 3778,
              DOI 10.17487/RFC3778, May 2004,
              <http://www.rfc-editor.org/info/rfc3778>.

   [RFC3864]  Klyne, G., Nottingham, M., and J. Mogul, "Registration
              Procedures for Message Header Fields", BCP 90, RFC 3864,
              DOI 10.17487/RFC3864, September 2004,
              <http://www.rfc-editor.org/info/rfc3864>.

   [RFC4270]  Hoffman, P. and B. Schneier, "Attacks on Cryptographic
              Hashes in Internet Protocols", RFC 4270,
              DOI 10.17487/RFC4270, November 2005,
              <http://www.rfc-editor.org/info/rfc4270>.

   [RFC4880]  Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R.
              Thayer, "OpenPGP Message Format", RFC 4880,
              DOI 10.17487/RFC4880, November 2007,
              <http://www.rfc-editor.org/info/rfc4880>.

   [RFC5321]  Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
              DOI 10.17487/RFC5321, October 2008,
              <http://www.rfc-editor.org/info/rfc5321>.

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RFC 7681              EESST Protocol Specification          October 2015

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,
              <http://www.rfc-editor.org/info/rfc5322>.

   [RFC5536]  Murchison, K., Ed., Lindsey, C., and D. Kohn, "Netnews
              Article Format", RFC 5536, DOI 10.17487/RFC5536, November
              2009, <http://www.rfc-editor.org/info/rfc5536>.

   [Sal84]    Saltzer, J., Reed, D., and D. Clark, "End-to-End Arguments
              in System Design", ACM Transactions on Computer
              Systems 2(4), DOI 10.1145/357401.357402, November 1984,
              <http://dx.doi.org/10.1145/357401.357402>.

   [Ste12]    Stewart, T., "Implementation Guide for the Postsecondary
              Electronic Standards Council XML Standard Format for the
              High School Transcript, Version 1.3.0", July 2012,
              <http://www.pesc.org/library/docs/standards/
              High%20School%20Transcript/XML%20HS%20Transcript%20Impl%20
              Guide%20Version%201.3.0%202012%2007%2026.pdf>.

   [XML11]    Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E.,
              Yergeau, F., and J. Cowan, "Extensible Markup Language
              (XML) 1.1 (Second Edition)", W3C Recommendation
              REC-xml11-20060816, August 2006,
              <http://www.w3.org/TR/2006/REC-xml11-20060816>.

   [XSD]      Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes
              Second Edition", W3C Recommendation
              REC-xmlschema-2-20041028, October 2004,
              <http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.

Acknowledgments

   Derek Atkins, Paul Hoffman, and Werner Koch provided independent
   reviews of this memo.  Fred Baker, Dave Crocker, Keith Moore, and
   Chris Newman provided comments and questions about drafts of this
   document.

Author's Address

   James R. Davin

   Email: info@EESST.org
   URI:   http://EESST.org/

Davin                         Informational                    [Page 40]