The SignerInfo.ComputeCounterSignature(CmsSigner) method creates a countersignature by using the specified signer and adds the signature to the CMS/PKCS #7 message. Countersignatures are restricted to one level.
- signer
A System.Security.Cryptography.Pkcs.CmsSigner object that represents the counter signer.
This implementation of CMS/PKCS #7 supports only one level of countersignature. That is, a signature can be signed, which forms a countersignature, but that countersignature cannot be signed again.
The following permissions are required to access the signature key: