private BCryptAlgorithmHandle GetSymmetricBlockCipherAlgorithmHandle(CngCbcAuthenticatedEncryptorConfiguration configuration)
{
// basic argument checking
if (String.IsNullOrEmpty(configuration.EncryptionAlgorithm))
{
throw Error.Common_PropertyCannotBeNullOrEmpty(nameof(EncryptionAlgorithm));
}
if (configuration.EncryptionAlgorithmKeySize < 0)
{
throw Error.Common_PropertyMustBeNonNegative(nameof(configuration.EncryptionAlgorithmKeySize));
}
_logger.OpeningCNGAlgorithmFromProviderWithChainingModeCBC(configuration.EncryptionAlgorithm, configuration.EncryptionAlgorithmProvider);
BCryptAlgorithmHandle?algorithmHandle = null;
// Special-case cached providers
if (configuration.EncryptionAlgorithmProvider == null)
{
if (configuration.EncryptionAlgorithm == Constants.BCRYPT_AES_ALGORITHM)
{
algorithmHandle = CachedAlgorithmHandles.AES_CBC;
}
}
// Look up the provider dynamically if we couldn't fetch a cached instance
if (algorithmHandle == null)
{
algorithmHandle = BCryptAlgorithmHandle.OpenAlgorithmHandle(configuration.EncryptionAlgorithm, configuration.EncryptionAlgorithmProvider);
algorithmHandle.SetChainingMode(Constants.BCRYPT_CHAIN_MODE_CBC);
}
// make sure we're using a block cipher with an appropriate key size & block size
AlgorithmAssert.IsAllowableSymmetricAlgorithmBlockSize(checked (algorithmHandle.GetCipherBlockLength() * 8));
AlgorithmAssert.IsAllowableSymmetricAlgorithmKeySize(checked ((uint)configuration.EncryptionAlgorithmKeySize));
// make sure the provided key length is valid
algorithmHandle.GetSupportedKeyLengths().EnsureValidKeyLength((uint)configuration.EncryptionAlgorithmKeySize);
// all good!
return(algorithmHandle);
}
private BCryptAlgorithmHandle GetHmacAlgorithmHandle(CngCbcAuthenticatedEncryptorConfiguration configuration)
{
// basic argument checking
if (String.IsNullOrEmpty(configuration.HashAlgorithm))
{
throw Error.Common_PropertyCannotBeNullOrEmpty(nameof(configuration.HashAlgorithm));
}
_logger.OpeningCNGAlgorithmFromProviderWithHMAC(configuration.HashAlgorithm, configuration.HashAlgorithmProvider);
BCryptAlgorithmHandle?algorithmHandle = null;
// Special-case cached providers
if (configuration.HashAlgorithmProvider == null)
{
if (configuration.HashAlgorithm == Constants.BCRYPT_SHA1_ALGORITHM)
{
algorithmHandle = CachedAlgorithmHandles.HMAC_SHA1;
}
else if (configuration.HashAlgorithm == Constants.BCRYPT_SHA256_ALGORITHM)
{
algorithmHandle = CachedAlgorithmHandles.HMAC_SHA256;
}
else if (configuration.HashAlgorithm == Constants.BCRYPT_SHA512_ALGORITHM)
{
algorithmHandle = CachedAlgorithmHandles.HMAC_SHA512;
}
}
// Look up the provider dynamically if we couldn't fetch a cached instance
if (algorithmHandle == null)
{
algorithmHandle = BCryptAlgorithmHandle.OpenAlgorithmHandle(configuration.HashAlgorithm, configuration.HashAlgorithmProvider, hmac: true);
}
// Make sure we're using a hash algorithm. We require a minimum 128-bit digest.
uint digestSize = algorithmHandle.GetHashDigestLength();
AlgorithmAssert.IsAllowableValidationAlgorithmDigestSize(checked (digestSize * 8));
// all good!
return(algorithmHandle);
}
private BCryptAlgorithmHandle GetSymmetricBlockCipherAlgorithmHandle(ILogger logger)
{
// basic argument checking
if (String.IsNullOrEmpty(EncryptionAlgorithm))
{
throw Error.Common_PropertyCannotBeNullOrEmpty(nameof(EncryptionAlgorithm));
}
if (EncryptionAlgorithmKeySize < 0)
{
throw Error.Common_PropertyMustBeNonNegative(nameof(EncryptionAlgorithmKeySize));
}
BCryptAlgorithmHandle algorithmHandle = null;
logger?.OpeningCNGAlgorithmFromProviderWithChainingModeGCM(EncryptionAlgorithm, EncryptionAlgorithmProvider);
// Special-case cached providers
if (EncryptionAlgorithmProvider == null)
{
if (EncryptionAlgorithm == Constants.BCRYPT_AES_ALGORITHM)
{
algorithmHandle = CachedAlgorithmHandles.AES_GCM;
}
}
// Look up the provider dynamically if we couldn't fetch a cached instance
if (algorithmHandle == null)
{
algorithmHandle = BCryptAlgorithmHandle.OpenAlgorithmHandle(EncryptionAlgorithm, EncryptionAlgorithmProvider);
algorithmHandle.SetChainingMode(Constants.BCRYPT_CHAIN_MODE_GCM);
}
// make sure we're using a block cipher with an appropriate key size & block size
CryptoUtil.Assert(algorithmHandle.GetCipherBlockLength() == 128 / 8, "GCM requires a block cipher algorithm with a 128-bit block size.");
AlgorithmAssert.IsAllowableSymmetricAlgorithmKeySize(checked ((uint)EncryptionAlgorithmKeySize));
// make sure the provided key length is valid
algorithmHandle.GetSupportedKeyLengths().EnsureValidKeyLength((uint)EncryptionAlgorithmKeySize);
// all good!
return(algorithmHandle);
}
