CryptoAPI in Windows will always verify the CRL signature when determining revocation status of a certificate. While CertVerifyCertRevocation can be used to validate certificates, we recommend developers validate certificates using CertGetCertificateChain in their code because it will construct a certificate chain, download all necessary CRLs and validate the certificate chain as defined by the IETF standard (RFC 3280) on certificate validation. Generally we recommend devs call CertGetCertificateChain and CertVerifyCertificateChainPolicy to validate certs rather than call WinVerifyTrust or build their own verification algorithm using APIs such as CertGetCRLFromStore, CertGetIssuerCertificateFromStore or CertVerifyRevocation. Finally, the CRL UI in Windows shows you what is in the CRL. Valid or not. But code in Windows validates the CRL when needed. I hope that helps... Cheers, Michael [Writing Secure Code 2nd Ed] http://www.microsoft.com/mspress/books/5957.asp [Protect Your PC] http://www.microsoft.com/protect [Blog] http://blogs.msdn.com/michael_howard
