internal static extern bool CryptCreateHash(
     SafeCryptoContextHandle cryptoContext,
     AlgorithmId algorithmId,
     SafeCryptoKeyHandle key,
     int flags,
     out SafeCryptoHashHandle hash);
 internal static extern bool CryptImportKey(
     SafeCryptoContextHandle cryptoContext, 
     byte[] key, 
     uint keyLength, 
     SafeCryptoKeyHandle pubKey, 
     CryptImportKeyFlags flags, 
     out SafeCryptoKeyHandle keyHandle);
 internal static extern bool CryptAcquireContext(
     out SafeCryptoContextHandle cryptoContext,
     String container,
     String provider,
     ProviderType providerType,   
     CryptoAcquireContextFlags flags);