Network Working Group J. Schaad Request for Comments: 5273 Soaring Hawk Consulting Category: Standards Track M. Myers TraceRoute Security, Inc. June 2008 Certificate Management over CMS (CMC): Transport Protocols Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
AbstractThis document defines a number of transport mechanisms that are used to move CMC (Certificate Management over CMS (Cryptographic Message Syntax)) messages. The transport mechanisms described in this document are HTTP, file, mail, and TCP. CMC-STRUCT]). 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 [MUST].
+---------------------+----------------+ | Message Type | File Extension | +---------------------+----------------+ | Simple PKI Request | .p10 | | Full PKI Request | .crq | | Simple PKI Response | .p7c | | Full PKI Response | .crp | +---------------------+----------------+ File PKI Request/Response Identification SMIMEV3]. When using a mail-based protocol, MIME wrapping between the layers of CMS wrapping is optional. Note that this is different from the standard S/MIME (Secure MIME) message. 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-Request". 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" extension MUST be specified as part of the content-type or content- disposition statement.
+--------------+------------------------+------------+--------------+ | Item | MIME Type | File | SMIME Type | | | | Extension | | +--------------+------------------------+------------+--------------+ | Simple PKI | application/pkcs10 | .p10 | N/A | | Request | | | | | Full PKI | application/pkcs7-mime | .p7m | CMC-request | | Request | | | | | Simple PKI | application/pkcs7-mime | .p7c | certs-only | | Response | | | | | Full PKI | application/pkcs7-mime | .p7m | CMC-response | | Response | | | | +--------------+------------------------+------------+--------------+ Table 1: MIME PKI Request/Response Identification HTTP] as a transport layer. In most circumstances, the use of HTTP over TLS [TLS] provides any necessary content protection from eavesdroppers. In order for CMC clients and servers using HTTP to interoperate, the following rules apply. Clients MUST use the POST method to submit their requests. Servers MUST use the 200 response code for successful responses. Clients MAY attempt to send HTTP requests using TLS 1.0 [TLS] or later, although servers are not required to support TLS. Servers MUST NOT assume client support for any type of HTTP authentication such as cookies, Basic authentication, or Digest authentication. Clients and servers are expected to follow the other rules and restrictions in [HTTP]. Note that some of those rules are for HTTP methods other than POST; clearly, only the rules that apply to POST are relevant for this specification. Table 1.
The body of the message is the binary value of the encoding of the PKI Request. Table 1. Section 6.6 of [CMC-STRUCT]. Developers of state-constrained PKI clients are strongly encouraged to incorporate the use of these attributes. Initiation of a secure communications channel between an end-entity and a CA or Registration Authority (RA) -- and, similarly, between an RA and another RA or CA -- necessarily requires an out-of-band trust initiation mechanism. For example, a secure channel may be constructed between the end-entity and the CA via IPsec [IPsec] or
TLS [TLS]. Many such schemes exist, and the choice of any particular scheme for trust initiation is outside the scope of this document. Implementers of this protocol are strongly encouraged to consider generally accepted principles of secure key management when integrating this capability within an overall security architecture. In some instances, no prior out-of-band trust will have been initiated prior to use of this protocol. This can occur when the protocol itself is being used to download onto the system the set of trust anchors to be used for these protocols. In these instances, the Enveloped Data content type (Section 188.8.131.52.3 in [CMC-STRUCT]) must be used to provide the same shrouding that TLS would have provided. [CMC-STRUCT] Schaad, J. and M. Myers, "Certificate Management over CMS (CMC)", RFC 5272, June 2008. [HTTP] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [IPsec] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, December 2005. [MUST] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, BCP 14, March 1997. [SMIMEV3] Ramsdell, B., "Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Message Specification", RFC 3851, July 2004.
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