private byte[]? ChangeKeyImpl(ReadOnlySpan <byte> key)
{
byte[]? modifiedKey = null;
// If _blockSize is -1 the key isn't going to be extractable by the object holder,
// so there's no point in recalculating it in managed code.
if (key.Length > _blockSize && _blockSize > 0)
{
// Perform RFC 2104, section 2 key adjustment.
modifiedKey = _hashAlgorithmId switch
{
HashAlgorithmNames.SHA256 => SHA256.HashData(key),
HashAlgorithmNames.SHA384 => SHA384.HashData(key),
HashAlgorithmNames.SHA512 => SHA512.HashData(key),
HashAlgorithmNames.SHA1 => SHA1.HashData(key),
HashAlgorithmNames.MD5 when Helpers.HasMD5 => MD5.HashData(key),
_ => throw new CryptographicException(SR.Format(SR.Cryptography_UnknownHashAlgorithm, _hashAlgorithmId)),
};
}
HashProvider?oldHashProvider = _hMacProvider;
_hMacProvider = null !;
oldHashProvider?.Dispose(true);
_hMacProvider = HashProviderDispenser.CreateMacProvider(_hashAlgorithmId, key);
return(modifiedKey);
}
private byte[]? ChangeKeyImpl(ReadOnlySpan <byte> key)
{
byte[]? modifiedKey = null;
// If _blockSize is -1 the key isn't going to be extractable by the object holder,
// so there's no point in recalculating it in managed code.
if (key.Length > _blockSize && _blockSize > 0)
{
// Perform RFC 2104, section 2 key adjustment.
if (_lazyHashProvider == null)
{
_lazyHashProvider = HashProviderDispenser.CreateHashProvider(_hashAlgorithmId);
}
_lazyHashProvider.AppendHashData(key);
modifiedKey = _lazyHashProvider.FinalizeHashAndReset();
}
HashProvider?oldHashProvider = _hMacProvider;
_hMacProvider = null !;
oldHashProvider?.Dispose(true);
_hMacProvider = HashProviderDispenser.CreateMacProvider(_hashAlgorithmId, key);
return(modifiedKey);
}
internal LiteHmac(string hashAlgorithmId, ReadOnlySpan <byte> key)
{
_provider = HashProviderDispenser.CreateMacProvider(hashAlgorithmId, key);
_hashSizeInBytes = _provider.HashSizeInBytes;
}