Patent ID: 7395428

Claim:
In a sending computer system that is network connectable over a trusted link to a server computer system, the sending computer system being configured to send electronic messages, a method for checking the validity of a digital certificate before using the digital certificate to generate a digital signature based on the digital certificate, the method comprising: an act of creating an electronic message including data that a sending entity intends to be delivered to a recipient entity; an act of receiving an indication that a private key is to be used to digitally sign the created electronic message; an act of identifying a digital certificate that binds the sending entity to the private key prior to digitally signing the message with a digital signature based on the private key; an act of sending a certificate validation request to the server computer system over the trusted link, the certificate validation request including certificate information representative of the identified digital certificate, the certificate information being at least enough information for a certificate authority to identify the identified digital certificate; an act of receiving a certificate status indication from the server computer system over the trusted link, the certificate status indication indicating the status of the identified digital certificate; an act of determining that the certificate status indication indicates that the status of the identified digital certificate is at least one of non-valid and compromised prior to digitally signing the message with a digital signature based on the private key; and based on the determination, an act of preventing generation of a digital signature based on the private key for the electronic message that corresponds to the non-valid and/or compromised digital certificate such that resource use for digital signature generation is avoided.