On Fri, Feb 26, 2016, Nounou Dadoun wrote: > I've extracted the certificates from the exchange to verify that the (tlsv1) successful handshake and the (tlsv1.2) failed handshake certificates are identical (they are) and I've also checked to make sure that the CA certificate that the server has for signature verification is the same as the CA certificate handed over by the client in the exchange (it is). > > I've also used the command line openssl verify to verify the certificate against the CA: > "client_cert_success.pem: OK" > > However it succeeds in TLSv1 and fails in TLSv1.2 (the one line change noted below). > > I've now attached the certificates for quick reference - can anyone see what might be causing the different behavior between TLSv1 and TLSv1.2? > The signature TLS uses for Client auth is different in TLS 1.2. For TLS < 1.2 the TLS signature is a combined MD5+SHA1 form for RSA. For TLS 1.2 it is the more standard DigestInfo signature which can use other algorithms such as SHA512 or SHA256. Steve. -- Dr Stephen N. Henson. OpenSSL project core developer. Commercial tech support now available see: http://www.openssl.org
