public Aes128CtrStorage(IStorage baseStorage, byte[] key, byte[] counter, bool leaveOpen)
: base(baseStorage, BlockSize, leaveOpen)
{
if (key == null)
{
throw new NullReferenceException(nameof(key));
}
if (key.Length != BlockSize)
{
throw new ArgumentException(nameof(key), $"Key must be {BlockSize} bytes long");
}
if (counter == null)
{
throw new NullReferenceException(nameof(counter));
}
if (counter.Length != BlockSize)
{
throw new ArgumentException(nameof(counter), $"Counter must be {BlockSize} bytes long");
}
// Make the stream seekable by remembering the initial counter value
for (int i = 0; i < 8; i++)
{
_counterOffset |= (long)counter[0xF - i] << (4 + i * 8);
}
_decryptor = new Aes128CtrTransform(key, counter);
Counter = _decryptor.Counter;
}
/// <summary>
/// Creates a new AES storage
/// </summary>
/// <param name="baseStorage">The input <see cref="IStorage"/>.</param>
/// <param name="key">The decryption key.</param>
/// <param name="counterOffset">Offset to add to the counter.</param>
/// <param name="counterHi">The value of the upper 64 bits of the counter. Can be null.</param>
/// <param name="leaveOpen"><see langword="true"/> to leave the storage open after the <see cref="Aes128CtrStorage"/> object is disposed; otherwise, <see langword="false"/>.</param>
public Aes128CtrStorage(IStorage baseStorage, byte[] key, long counterOffset, byte[] counterHi, bool leaveOpen)
: base(baseStorage, BlockSize, leaveOpen)
{
if (key == null)
{
throw new NullReferenceException(nameof(key));
}
if (key.Length != BlockSize)
{
throw new ArgumentException(nameof(key), $"Key must be {BlockSize} bytes long");
}
var initialCounter = new byte[BlockSize];
if (counterHi != null)
{
Array.Copy(counterHi, initialCounter, 8);
}
_counterOffset = counterOffset;
_decryptor = new Aes128CtrTransform(key, initialCounter);
Counter = _decryptor.Counter;
}