1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T X.1341 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2015) SERIES X: DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY Secure applications and services PKI related Recommendations Certified mail transport and cer
2、tified post office protocols Recommendation ITU-T X.1341 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY PUBLIC DATA NETWORKS X.1X.199 OPEN SYSTEMS INTERCONNECTION X.200X.299 INTERWORKING BETWEEN NETWORKS X.300X.399 MESSAGE HANDLING SYSTEMS X.400X.499 DIRECTORY
3、X.500X.599 OSI NETWORKING AND SYSTEM ASPECTS X.600X.699 OSI MANAGEMENT X.700X.799 SECURITY X.800X.849 OSI APPLICATIONS X.850X.899 OPEN DISTRIBUTED PROCESSING X.900X.999 INFORMATION AND NETWORK SECURITY General security aspects X.1000X.1029 Network security X.1030X.1049 Security management X.1050X.10
4、69 Telebiometrics X.1080X.1099 SECURE APPLICATIONS AND SERVICES Multicast security X.1100X.1109 Home network security X.1110X.1119 Mobile security X.1120X.1139 Web security X.1140X.1149 Security protocols X.1150X.1159 Peer-to-peer security X.1160X.1169 Networked ID security X.1170X.1179 IPTV securit
5、y X.1180X.1199 CYBERSPACE SECURITY Cybersecurity X.1200X.1229 Countering spam X.1230X.1249 Identity management X.1250X.1279 SECURE APPLICATIONS AND SERVICES Emergency communications X.1300X.1309 Ubiquitous sensor network security X.1310X.1339 PKI related Recommendations X.1340X.1349 CYBERSECURITY IN
6、FORMATION EXCHANGE Overview of cybersecurity X.1500X.1519 Vulnerability/state exchange X.1520X.1539 Event/incident/heuristics exchange X.1540X.1549 Exchange of policies X.1550X.1559 Heuristics and information request X.1560X.1569 Identification and discovery X.1570X.1579 Assured exchange X.1580X.158
7、9 CLOUD COMPUTING SECURITY Overview of cloud computing security X.1600X.1601 Cloud computing security design X.1602X.1639 Cloud computing security best practices and guidelines X.1640X.1659 Cloud computing security implementation X.1660X.1679 Other cloud computing security X.1680X.1699 For further d
8、etails, please refer to the list of ITU-T Recommendations. Rec. ITU-T X.1341 (09/2015) i Recommendation ITU-T X.1341 Certified mail transport and certified post office protocols Summary Recommendation ITU-T X.1341 defines the certified mail transfer protocol (CMTP) and certified post office protocol
9、 (CPOP) in order to foster exchange of electronic certified mails worldwide in a secure way by providing confidentiality, identification of the correspondents, integrity and non-repudiation. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T X.1341 2015-09-17 17 11.1002/1000/12
10、352 Keywords Certified mail transfer protocol, certified post office protocol, CMTP, confidentiality, CPOP, integrity, non-repudiation, POP, post office protocol, security, simple mail transfer protocol, SMTP. _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field
11、of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T X.1341 (09/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information an
12、d communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide ba
13、sis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Reso
14、lution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration
15、 and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions ar
16、e met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the pos
17、sibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the
18、 Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest informati
19、on and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2016 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T X.1341 (09/2015) iii Table of Contents
20、 Page 1 Scope . 1 2 References . 1 3 Definitions 2 4 Abbreviations and acronyms 3 5 Conventions 4 6 Certified mail basic concepts 4 7 Types of certified mail commands . 4 7.1 Types of CMTP commands 5 7.2 Types of CPOP commands . 5 8 Detailed CMTP specification . 7 8.1 CELO: Ask for delivery type lis
21、t 7 8.2 Delivery type list 7 8.3 Selected delivery type . 8 8.4 Delivery type acknowledgement 8 8.5 Senders e-mail address. 8 8.6 Senders e-mail acknowledgement . 8 8.7 Ask for sending e-mail to recipient 8 8.8 Check recipients e-mail address by the remote Cmail server 8 8.9 Recipients e-mail addres
22、s acknowledgement 9 8.10 Recipients e-mail acknowledgement . 9 8.11 Ask for sending ENVELOPE . 9 8.12 Ready to receive ENVELOPE 10 8.13 ENVELOPE . 10 8.14 Server signed notice of deposit . 10 8.15 Sender and server signed notice of deposit 10 8.16 ENVELOPE between Cmail servers 11 8.17 Signed notice
23、 of transit between Cmail servers . 11 8.18 Signed notice of transit . 11 9 Certified post office protocol (CPOP) 12 9.1 Ask for pending messages 12 9.2 Challenge recipient and server signed notice of reception . 12 9.3 Challenge response and recipient and server signed notice of reception . 13 9.4
24、ENVELOPE . 14 9.5 Recipient and server signed notice of reception between Cmail servers (optional) 14 9.6 Recipient and server signed notice of reception . 14 Annex A Notices in XML schema definition (XSD) 15 A.1 XSD overview 15 iv Rec. ITU-T X.1341 (09/2015) Page A.2 Formal specification of notices
25、 in XSD . 18 Annex B Notices in ASN.1 . 22 Annex C Requirements on public-key infrastructure components . 26 C.1 Introduction 26 C.2 Cmail server end-entity public-key certificates 26 C.3 Cmail client end-entity public-key certificates . 26 C.4 Information validation requirements 27 Annex D Requirem
26、ents on transport layer security (TLS) . 28 Annex E Object identifiers defined in this Recommendation . 29 Appendix I Envelope and notices format 30 I.1 Notice of deposit . 30 I.2 Notice of reception . 30 I.3 Notice of transit 31 I.4 ENVELOPE . 32 Bibliography. 33 Rec. ITU-T X.1341 (09/2015) v Intro
27、duction This Recommendation extends the capabilities of the simple mail transfer protocol (SMTP) and post office protocol version 3 (POP3) to support authentication, security and non-repudiation. For this purpose, two protocols are specified: the certified mail transfer protocol (CMTP), which is an
28、extension to the simple mail transfer protocol (SMTP), is the protocol supporting the communications between the sender of e-mails and a mail server, called the certified mail (Cmail) server; the certified post office protocol (CPOP), which is an extension to the post office protocol version 3 (POP3
29、), is the protocol supporting the communications between the recipient of e-mails and the Cmail server. Within SMTP and POP3, a message type is identified by a command, i.e., a keyword at the start of the message. For CMTP and CPOP, new commands have been defined and some of the SMTP and POP3 comman
30、ds have been extended. In particular, some commands have been extended to carry notices (electronic documents) allowing the different stages of the communication from the sender to the recipient to be documented and verified. CMTP and CPOP also introduce the concept of Cmail server that is an active
31、 partner in the communication between the sender and the recipient allowing it to certify that the exchange between two parties has indeed occurred. Certified mail assumes that an existing public-key infrastructure (PKI) is established. Annex A, which is an integral part of this Recommendation, prov
32、ides the formal specification for notices using the XML schema definition (XSD) notation technique. Annex B, which is an integral part of this Recommendation, provides the formal specification for notices using the abstract syntax notation one (ASN.1). Annex C, which is an integral part of this Reco
33、mmendation, specifies the requirements for public-key certificates issued to clients (sender and recipient of e-mails) and Cmail servers. Annex D, which is an integral part of this Recommendation, specifies requirements on the use of the transport layer security (TLS) specification. Annex E, which i
34、s an integral part of this Recommendation, specifies object identifiers defined for Cmail servers. Rec. ITU-T X.1341 (09/2015) 1 Recommendation ITU-T X.1341 Certified mail transport and certified post office protocols 1 Scope This Recommendation specifies how to make e-mails reliable in terms of ide
35、ntification and confidentiality. Certified mail transfer protocol/certified post office protocol (CMTP/CPOP) enables: the solution of repudiation issues because of the use of electronic signature; the solution of confidentiality issues because of the use of encryption; the production of reliable not
36、ices of deposit, notices of transit and notices of reception; the use of a certified mail (Cmail) server to track certified mails to avoid their loss during the process; the use of a transport layer security (TLS) connection to provide stronger identification. This stronger level of identification i
37、s required by the Cmail server. Conformity with this Recommendation is not to be taken as any proof of evidence for claiming compliance with any national or regional law, regulation or policy. The technical, organizational and procedural means described in this Recommendation do not guarantee in any
38、 way the constitution of any level of security that may be put upon certain correspondence by specific national or regional law, regulation or policy. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions
39、 of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations an
40、d other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T X.520 Recommendation ITU-T X.520 (2012) | ISO/IEC 959
41、4-6:2014, Information technology Open Systems Interconnection The Directory: Selected attribute types. ITU-T X.680 Recommendation ITU-T X.680 (2008) | ISO/IEC 8824-1:2008, Information technology Abstract Syntax Notation One (ASN.1): Specification of basic notation. ITU-T X.690 Recommendation ITU-T X
42、.690 (2008) | ISO/IEC 8825-1: 2008, Information technology ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER). ITU-T X.693 Recommendation ITU-T X.693 (2008) | ISO/IEC 8825-4: 2008, Information technology ASN.1 enco
43、ding rules: XML Encoding Rules (XER). ISO 3166-1 ISO 3166-1:2013, Codes for the representation of names of countries and their subdivisions Part 1: Country codes. 2 Rec. ITU-T X.1341 (09/2015) IETF RFC 822 IETF RFC 822 (1982), Standard for the format of ARPA Internet text messages. IETF RFC 1939 IET
44、F RFC 1939 (1996), Post office protocol Version 3. IETF RFC 2045 IETF RFC 2045 (1996), Multipurpose internet mail extensions (MIME) Part One: Format of internet message bodies. IETF RFC 5246 IETF RFC 5246 (2008), The transport layer security (TLS) Protocol Version 1.2. IETF RFC 5321 IETF RFC 5321 (2
45、008), Simple mail transfer protocol. XML W3C Recommendation XML1.0 (2000), Extensible markup language (XML) 1.0 (fifth edition). XSD W3C Recommendation XML Schema (2001), XML schema Part 1: Structures. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined els
46、ewhere: 3.1.1 certification authority (CA) b-ITU-T X.509: An authority trusted by one or more users to create and assign public-key certificates. Optionally the certification authority may create the subjects keys. 3.1.2 certificate validation b-ITU-T X.509: The process of ensuring that a certificat
47、e was valid at a given time, including possibly the construction and processing of a certification path, and ensuring that all certificates in that path were valid (i.e., were not expired or revoked) at that given time. 3.1.3 hash function b-ITU-T X.509: A (mathematical) function which maps values f
48、rom a large (possibly very large) domain into a smaller range. A “good“ hash function is such that the results of applying the function to a (large) set of values in the domain will be evenly distributed (and apparently at random) over the range. 3.1.4 private key b-ITU-T X.509: (In a public key cry
49、ptosystem) that key of an entitys key pair which is known only by that entity. 3.1.5 public key b-ITU-T X.509: (In a public key cryptosystem) that key of a users key pair which is publicly known. 3.1.6 public-key certificate (PKC) b-ITU-T X.509: The public key of a user, together with some other information, rendered unforgeable by digital signature with the private key of the CA which issued it. 3.1.7 public-key i
