public Aes128CtrEncryptedSource(ISource source, ICtrModeEncryptor encryptor, int generation, long baseOffset)
{
this.m_crypto = encryptor;
this.BlockSize = 16;
this.Generation = generation;
this.BaseOffset = baseOffset;
this.m_source = (ISource) new AlignedSource(source, this.BlockSize);
}
public ByteData PullData(long offset, int size)
{
ByteData byteData = this.m_source.PullData(offset, size);
if (byteData.Buffer.Count == 0)
{
return(new ByteData(new ArraySegment <byte>()));
}
ulong num = (ulong)(this.BaseOffset + offset) / (ulong)this.BlockSize;
byte[] numArray1 = new byte[this.m_crypto.KeySize];
for (int index = 0; index < 4; ++index)
{
numArray1[7 - index] = (byte)(this.Generation >> index * 8 & (int)byte.MaxValue);
}
for (int index = 0; index < 8; ++index)
{
numArray1[15 - index] = (byte)(num >> index * 8 & (ulong)byte.MaxValue);
}
byte[] numArray2 = new byte[byteData.Buffer.Count];
ICtrModeEncryptor crypto = this.m_crypto;
byte[] iv = numArray1;
ArraySegment <byte> buffer = byteData.Buffer;
byte[] array1 = buffer.Array;
buffer = byteData.Buffer;
int offset1 = buffer.Offset;
buffer = byteData.Buffer;
int count1 = buffer.Count;
byte[] dst = numArray2;
int dstOffset = 0;
crypto.EncryptBlock(iv, array1, offset1, count1, dst, dstOffset);
byte[] array2 = numArray2;
int offset2 = 0;
buffer = byteData.Buffer;
int count2 = buffer.Count;
return(new ByteData(new ArraySegment <byte>(array2, offset2, count2)));
}