title: SignedCms.CheckSignature() with renewed cert -> new serial?
body: <p>i am using</p>
  
  <p>SignedCms.CheckSignature(certColl, true)</p>
  
  <p>(with only one cert in certColl) to verify the signature of a pkcs-7 message. My problem is that i dont want to change the (public part of the) signers certificate on my server after the signer has renewed his certificate :-( The public key, issuer and subject are remaining unchanged after signer has renewed his certificate! So this has to work - at least in my opinion, even if i´m not a crypto-geek :-)  </p>
  
  <p>..but, unfortunately the .NET-Framework throws a Cryptographic Exception "Cannot find the original signer" like the stacktrace says exactly at:</p>
  
  <p>SignerInfo.CheckSignature(X509Certificate2Collection extraStore, Boolean verifySignatureOnly)</p>
  
  <p>This must be because the serial number of the signers certificate has changed and the SignerIdentifier property is readonly and set to IssuerAndSerialNumber. </p>
  
  <p>Does anyone know how workaround this? </p>
  
  <p>Or do i have to implement a "handmade" signature verifying with sth like: signedMessage.ComputeSignature(signer, false)?</p>
  
  <p>Thanks in advance and happy programming,
  Krile</p>