/**
* verify that the given certificate successfully handles and confirms
* the signature associated with this signer and, if a signingTime
* attribute is available, that the certificate was valid at the time the
* signature was generated.
*/
public bool Verify(
X509Certificate cert)
{
Time signingTime = GetSigningTime();
if (signingTime != null)
{
cert.CheckValidity(signingTime.Date);
}
return(DoVerify(cert.GetPublicKey()));
}
private Time GetSigningTime()
{
Asn1Object validSigningTime = GetSingleValuedSignedAttribute(
CmsAttributes.SigningTime, "signing-time");
if (validSigningTime == null)
{
return(null);
}
try
{
return(Time.GetInstance(validSigningTime));
}
catch (ArgumentException)
{
throw new CmsException("signing-time attribute value not a valid 'Time' structure");
}
}