User Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C; InfoPath.3; MS-RTC LM 8) Steps to reproduce: 1) Sent a digitally signed email 2) Verify that Thunderbird can read and validate digital signature 3) Revoke the signing certificate 4) Re-read the email message Certificate status shows that the signature is not valid because the certificate authority is not trusted to issue this type of certificate. The message should be that the certificate has been revoked. 5) Send another signed email issued by the same certificate authority and see that this signature is trusted. Fedora 17 - Thunderbird 17.0.6 Actual results: An incorrect message security error occurs. This message includes a digital signature, but the signature is invalid. The certificate used to sign the message was issued by a certificate authority that you do not trust for issuing this kind of certificate. Expected results: The error should be that the digital signature certificate is invalid because it has been revoked.