Internet X.509 Public Key Infrastructure (PKI) Proxy ... - Clizio.com

RFC 3820 X.509 Proxy Certificate Profile June 2004For example, a Proxy Issuer MAY use a sequentially assigned integeror a UUID to assign a unique serial number to a PC it issues. Or aProxy Issuer MAY use a SHA-1 hash of the PC public key to assign aserial number with a high probability of uniqueness.3.4. SubjectThe subject field of a Proxy Certificate MUST be the issuer field(that is the subject of the Proxy Issuer) appended with a singleCommon Name component.The value of the Common Name SHOULD be unique to each ProxyCertificate bearer amongst all Proxy Certificates with the sameissuer.If a Proxy Issuer issues two proxy certificates to the same bearer,the Proxy Issuer MAY choose to use the same Common Name for both.Examples of this include Proxy Certificates for different uses (e.g.,signing vs encryption) or the re-issuance of an expired ProxyCertificate.The Proxy Issuer MAY use an approach to assigning Common Name valuesthat merely ensures a high probability of uniqueness. This value MAYbe the same value used for the serial number.The result of this approach is that all subject names of ProxyCertificates are derived from the name of the issuing EEC (it will bethe first part of the subject name appended with one or more CNcomponents) and are unique to each bearer.3.5. Subject Alternative NameThe subjectAltName extension MUST NOT be present in a ProxyCertificate.3.6. Key Usage and Extended Key UsageIf the Proxy Issuer certificate has a Key Usage extension, theDigital Signature bit MUST be asserted.This document places no constraints on the presence or contents ofthe key usage and extended key usage extension. However, section 4.2explains what functions should be allowed a proxy certificate by arelying party.Tuecke, et al. Standards Track [Page 13]