OCSP

This specification defines a profile of the Online Certificate Status

Protocol (OCSP) that addresses the scalability issues inherent when

using OCSP in large scale (high volume) Public Key Infrastructure

(PKI) environments and/or in PKI environments that require a

lightweight solution to minimize communication bandwidth and client-

side processing.

This specification obsoletes RFC 5019. The profile specified in RFC

5019 has been updated to allow and recommend the use of SHA-256 over

SHA-1.

RFC 8954 imposed size constraints on the optional Nonce extension for the Online Certificate Status Protocol (OCSP). OCSP is used to check the status of a certificate, and the Nonce extension is used to cryptographically bind an OCSP response message to a particular OCSP request message.

Some environments use cryptographic algorithms that generate a Nonce value that is longer than 32 octets. This document also modifies the "Nonce" section of RFC 6960 to clearly define and differentiate the encoding format and values for easier implementation and understanding. This document obsoletes RFC 8954, which includes updated ASN.1 modules for OCSP, and updates RFC 6960.

Public key certificates need to be revoked when they are compromised, that is, when the associated private key is exposed to an unauthorized entity. However, the revocation process is often unreliable. An alternative to revocation is issuing a sequence of certificates, each with a short validity period, and terminating the sequence upon compromise. This memo proposes an Automated Certificate Management Environment (ACME) extension to enable the issuance of Short-Term, Automatically Renewed (STAR) X.509 certificates.

This document specifies a protocol useful in determining the current status of a digital certificate without requiring Certificate Revocation Lists (CRLs). Additional mechanisms addressing PKIX operational requirements are specified in separate documents. This document obsoletes RFCs 2560 and 6277. It also updates RFC 5912.

This document defines a set of Secure/Multipurpose Internet Mail Extensions (S/MIME) Capability types for ASN.1 encoding for the current set of public keys defined by the PKIX working group. This facilitates the ability for a requester to specify information on the public keys and signature algorithms to be used in responses. "Online Certificate Status Protocol Algorithm Agility" (RFC 6277) details an example of where this is used. This document is not an Internet Standards Track specification; it is published for informational purposes.

The Cryptographic Message Syntax (CMS) allows revocation information to be conveyed as part of the SignedData, EnvelopedData, AuthenticatedData, and AuthEnvelopedData content types. The preferred format for revocation information is the Certificate Revocation List (CRL), but an extension mechanism supports other revocation information formats. This document defines two additional revocation information formats for Online Certificate Status Protocol (OCSP) responses and Server-Based Certificate Validation Protocol (SCVP) requests and responses. [STANDARDS-TRACK]

While the Internet Key Exchange Protocol version 2 (IKEv2) supports public key based authentication, the corresponding use of in-band Certificate Revocation Lists (CRL) is problematic due to unbounded CRL size. The size of an Online Certificate Status Protocol (OCSP) response is however well-bounded and small. This document defines the "OCSP Content" extension to IKEv2. A CERTREQ payload with "OCSP Content" identifies zero or more trusted OCSP responders and is a request for inclusion of an OCSP response in the IKEv2 handshake. A cooperative recipient of such a request responds with a CERT payload containing the appropriate OCSP response. This content is recognizable via the same "OCSP Content" identifier.

When certificates are used with IKEv2, the communicating peers need a mechanism to determine the revocation status of the peer's certificate. OCSP is one such mechanism. This document applies when OCSP is desired and security policy prevents one of the IKEv2 peers from accessing the relevant OCSP responder directly. Firewalls are often deployed in a manner that prevents such access by IKEv2 peers outside of an enterprise network. [STANDARDS-TRACK]

This document defines a mechanism to enable in-band transmission of Online Certificate Status Protocol (OCSP) responses in the Kerberos network authentication protocol. These responses are used to verify the validity of the certificates used in Public Key Cryptography for Initial Authentication in Kerberos (PKINIT), which is the Kerberos Version 5 extension that provides for the use of public key cryptography. [STANDARDS-TRACK]