1. Abstract

This document specifies a protocol useful in determining the current status of a digital certificate without requiring CRLs. Additional mechanisms addressing PKIX operational requirements are specified in separate documents.

An overview of the protocol is provided in section 2. Functional requirements are specified in section 4. Details of the protocol are in section 5. We cover security issues with the protocol in section 6. Appendix A defines OCSP over HTTP, appendix B accumulates ASN.1 syntactic elements and appendix C specifies the mime types for the messages.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document (in uppercase, as shown) are to be interpreted as described in [RFC2119].