/// <summary>
/// Creates an instance of SqlAes256CbcAlgorithm class with a given key
/// </summary>
/// <param name="encryptionKey">Root key</param>
/// <param name="encryptionType">Encryption Type. Expected values are either Determinitic or Randomized.</param>
/// <param name="encryptionAlgorithm">Encryption Algorithm.</param>
/// <returns></returns>
internal override SqlClientEncryptionAlgorithm Create(SqlClientSymmetricKey encryptionKey, SqlClientEncryptionType encryptionType, string encryptionAlgorithm)
{
// Callers should have validated the encryption algorithm and the encryption key
Debug.Assert(encryptionKey != null);
Debug.Assert(string.Equals(encryptionAlgorithm, SqlAes256CbcAlgorithm.AlgorithmName, StringComparison.OrdinalIgnoreCase) == true);
// Validate encryption type
if (!((encryptionType == SqlClientEncryptionType.Deterministic) || (encryptionType == SqlClientEncryptionType.Randomized)))
{
throw SQL.InvalidEncryptionType(SqlAes256CbcAlgorithm.AlgorithmName,
encryptionType,
SqlClientEncryptionType.Deterministic,
SqlClientEncryptionType.Randomized);
}
// Get the cached encryption algorithm if one exists or create a new one, add it to cache and use it
//
// For now, we only have one version. In future, we may need to parse the algorithm names to derive the version byte.
const byte algorithmVersion = 0x1;
StringBuilder algorithmKeyBuilder = new StringBuilder(Convert.ToBase64String(encryptionKey.RootKey), SqlSecurityUtility.GetBase64LengthFromByteLength(encryptionKey.RootKey.Length) + 4 /*separators, type and version*/);
#if DEBUG
int capacity = algorithmKeyBuilder.Capacity;
#endif //DEBUG
algorithmKeyBuilder.Append(":");
algorithmKeyBuilder.Append((int)encryptionType);
algorithmKeyBuilder.Append(":");
algorithmKeyBuilder.Append(algorithmVersion);
string algorithmKey = algorithmKeyBuilder.ToString();
#if DEBUG
Debug.Assert(algorithmKey.Length <= capacity, "We needed to allocate a larger array");
#endif //DEBUG
SqlAes256CbcAlgorithm aesAlgorithm;
if (!_encryptionAlgorithms.TryGetValue(algorithmKey, out aesAlgorithm))
{
SqlAeadAes256CbcHmac256EncryptionKey encryptedKey = new SqlAeadAes256CbcHmac256EncryptionKey(encryptionKey.RootKey, SqlAes256CbcAlgorithm.AlgorithmName);
aesAlgorithm = new SqlAes256CbcAlgorithm(encryptedKey, encryptionType, algorithmVersion);
// In case multiple threads reach here at the same time, the first one adds the value
// the second one will be a no-op, the allocated memory will be claimed by Garbage Collector.
_encryptionAlgorithms.TryAdd(algorithmKey, aesAlgorithm);
}
return(aesAlgorithm);
}
/// <summary>
/// Initializes a new instance of SqlAeadAes256CbcHmac256Algorithm algorithm with a given key and encryption type
/// </summary>
/// <param name="encryptionKey">
/// Root encryption key from which three other keys will be derived
/// </param>
/// <param name="encryptionType">Encryption Type, accepted values are Deterministic and Randomized.
/// For Deterministic encryption, a synthetic IV will be genenrated during encryption
/// For Randomized encryption, a random IV will be generated during encryption.
/// </param>
/// <param name="algorithmVersion">
/// Algorithm version
/// </param>
internal SqlAeadAes256CbcHmac256Algorithm(SqlAeadAes256CbcHmac256EncryptionKey encryptionKey, SqlClientEncryptionType encryptionType, byte algorithmVersion)
{
_columnEncryptionKey = encryptionKey;
_algorithmVersion = algorithmVersion;
_version[0] = algorithmVersion;
Debug.Assert(null != encryptionKey, "Null encryption key detected in AeadAes256CbcHmac256 algorithm");
Debug.Assert(0x01 == algorithmVersion, "Unknown algorithm version passed to AeadAes256CbcHmac256");
// Validate encryption type for this algorithm
// This algorithm can only provide randomized or deterministic encryption types.
if (encryptionType == SqlClientEncryptionType.Deterministic)
{
_isDeterministic = true;
}
else
{
Debug.Assert(SqlClientEncryptionType.Randomized == encryptionType, "Invalid Encryption Type detected in SqlAeadAes256CbcHmac256Algorithm, this should've been caught in factory class");
}
_cryptoProviderPool = new ConcurrentQueue <AesCryptoServiceProvider>();
}
/// <summary>
/// Initializes a new instance of SqlAes256CbcAlgorithm algorithm with a given key and encryption type
/// </summary>
/// <param name="encryptionKey">
/// Root encryption key from which three other keys will be derived
/// </param>
/// <param name="encryptionType">Encryption Type, accepted values are Deterministic and Randomized.
/// For Deterministic encryption, a synthetic IV will be genenrated during encryption
/// For Randomized encryption, a random IV will be generated during encryption.
/// </param>
/// <param name="algorithmVersion">
/// Algorithm version
/// </param>
internal SqlAes256CbcAlgorithm(SqlAeadAes256CbcHmac256EncryptionKey encryptionKey, SqlClientEncryptionType encryptionType, byte algorithmVersion)
: base(encryptionKey, encryptionType, algorithmVersion)
{
}
