PKIX Working Group J. Schaad Internet Draft Soaring Hawk Consulting Document: draft-ietf-pkix-cmc-trans-02.txt M.Myers February 2005 TraceRoute Security Expires: July 2005 X.Liu Cisco J. Weinstein CMC Transport Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 . By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Comments or suggestions for improvement may be made on the "ietf- pkix" mailing list, or directly to the author. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. Abstract This document defines a number of transport mechanisms that are used to move [CMC] messages. The transport mechanisms described in this document are: HTTP, file, mail and TCP. 1. Overview This document defines a number of transport methods that are used to move [CMC] messages. The transport mechanisms described in this document are: HTTP, file, mail and TCP.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC 2119]. 2. File based protocol Enrollment messages and responses may be transferred between clients and servers using file system-based mechanisms, such as when enrollment is performed for an off-line client. When files are used to transport binary, BER-encoded Full Enrollment Request and Response messages, there MUST be only one instance of a request or response message in a single file. The following file type extensions SHOULD be used: Message Type File Extension Full PKI Request .crq Full PKI Response .crp 3. Mail based protocol MIME wrapping is defined for those environments that are MIME native. The basic mime wrapping in this section is taken from [SMIMEV2] and [SMIMEV3]. Simple enrollment requests are encoded using the "application/pkcs10" content type. A file name MUST be included either in a content type or a content disposition statement. The extension for the file MUST be ".p10". Simple enrollment response messages MUST be encoded as content-type "application/pkcs7-mime". An smime-type parameter MUST be on the content-type statement with a value of "certs-only." A file name with the ".p7c" extension MUST be specified as part of the content- type or content-disposition statement. Full enrollment request messages MUST be encoded as content-type "application/pkcs7-mime". The smime-type parameter MUST be included with a value of "CMC-enroll". A file name with the ".p7m" extension MUST be specified as part of the content-type or content-disposition statement. Full enrollment response messages MUST be encoded as content-type "application/pkcs7-mime". The smime-type parameter MUST be included with a value of "CMC-response." A file name with the ".p7m" extensions MUST be specified as part of the content-type or content- disposition statement. MIME TYPE File Extension SMIME-TYPE application/pkcs10 .p10 N/A (simple PKI request) application/pkcs7-mime .p7m CMC-request
(full PKI request) application/pkcs7-mime .p7c certs-only (simple PKI response) application/pkcs7-mime .p7m CMC-response (full PKI response) 4. HTTP/HTTPS based protocol HTTP messages are wrapped with by a mime object as specified above. 5. TCP based protocol When CMC messages are sent over a TCP-Based connection, no wrapping is required of the message. Messages are sent in their binary encoded form. The connection is closed by the server after generating a response for the client. (All CMC request messages from client to server generate a response message.) If a second set of messages from the client to the server is required to complete the transaction, the client generates a new TCP-Based connection for this purpose; it cannot reuse an existing one. Out of band setup can be used to keep a TCP-Based connection open for more than one message pair. A situation where this can occur is an RA talking to a CA over a specially setup TCP connection. 6 Socket-Based Transport When enrollment messages and responses are sent over sockets, no wrapping is required. Messages MUST be sent in their binary, BER- encoded form. 7. Security Considerations Mechanisms for thwarting replay attacks may be required in particular implementations of this protocol depending on the operational environment. In cases where the CA maintains significant state information, replay attacks may be detectable without the inclusion of the optional nonce mechanisms. Implementers of this protocol need to carefully consider environmental conditions before choosing whether or not to implement the senderNonce and recipientNonce attributes described in section 5.6. Developers of state-constrained PKI clients are strongly encouraged to incorporate the use of these attributes. 8. Acknowledgments The authors would like to thank Brian LaMacchia for his work in developing and writing up many of the concepts presented in this document. The authors would also like to thank Alex Deacon and Barb Fox for their contributions. 9. References
[CMC] J. Schaad, M. Myers, X. Liu, J. Weinstein, "Certificate Management Messages over CMS", draft-ietf-pkix-cmc-base-03.txt. [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [SMIMEV2] Dusse, S., Hoffman, P., Ramsdell, B., Lundblade, L. and L. Repka, "S/MIME Version 2 Message Specification", RFC 2311, March 1998. [SMIMEV3] Ramsdell, B., "S/MIME Version 3 Message Specification", RFC 2633, June 1999. 10. Authors' Addresses Jim Schaad Soaring Hawk Consulting EMail: firstname.lastname@example.org Michael Myers TraceRoute Security, Inc. EMail: email@example.com Xiaoyi Liu Cisco Systems 170 West Tasman Drive San Jose, CA 95134 Phone: (480) 526-7430 EMail: firstname.lastname@example.org Jeff Weinstein EMail: email@example.com Copyright Statement Copyright (C) The Internet Society (year). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights." "This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society.