Verifying a Countersignature
To verify a countersignature
- Call CryptMsgOpenToDecode to get a handle to the signed message.
- Get a pointer to the countersigner's certificate ( CERT_INFO).
- Call CryptMsgGetParam to retrieve the signer information from the message.
- Call CryptMsgGetParam to retrieve the countersignature from the message.
- Call CryptMsgVerifyCountersignatureEncoded to verify the countersignature.
If the CryptMsgVerifyCountersignatureEncoded function call succeeds, the countersignature is verified.