private static void CheckHashes(SignerInfoCollection signers)
        {
            if ((signers == null) || (signers.Count < 1))
            {
                throw new CryptographicException(-2146885618);
            }
            SignerInfoEnumerator enumerator = signers.GetEnumerator();

            while (enumerator.MoveNext())
            {
                SignerInfo current = enumerator.Current;
                if (current.SignerIdentifier.Type == SubjectIdentifierType.NoSignature)
                {
                    current.CheckHash();
                }
            }
        }