/**
*/
private byte[] ComputeOwnerKey(byte[] userPad, byte[] ownerPad)
{
byte[] ownerKey = new byte[32];
byte[] digest = DigestAlgorithms.Digest("MD5", ownerPad);
if (revision == STANDARD_ENCRYPTION_128 || revision == AES_128)
{
byte[] mkey = new byte[keyLength / 8];
// only use for the input as many bit as the key consists of
for (int k = 0; k < 50; ++k)
{
Array.Copy(DigestAlgorithms.Digest("MD5", digest, 0, mkey.Length), 0, digest, 0, mkey.Length);
}
Array.Copy(userPad, 0, ownerKey, 0, 32);
for (int i = 0; i < 20; ++i)
{
for (int j = 0; j < mkey.Length; ++j)
{
mkey[j] = (byte)(digest[j] ^ i);
}
rc4.PrepareARCFOURKey(mkey);
rc4.EncryptARCFOUR(ownerKey);
}
}
else
{
rc4.PrepareARCFOURKey(digest, 0, 5);
rc4.EncryptARCFOUR(userPad, ownerKey);
}
return(ownerKey);
}
protected internal virtual byte[] ComputeOwnerKey(byte[] userPad, byte[] ownerPad)
{
byte[] ownerKey = new byte[32];
byte[] digest = md5.Digest(ownerPad);
arcfour.PrepareARCFOURKey(digest, 0, 5);
arcfour.EncryptARCFOUR(userPad, ownerKey);
return(ownerKey);
}
public override void Write(byte[] b, int off, int len)
{
if (aes)
{
byte[] b2 = cipher.Update(b, off, len);
if (b2 == null || b2.Length == 0)
{
return;
}
outc.Write(b2, 0, b2.Length);
}
else
{
byte[] b2 = new byte[Math.Min(len, 4192)];
while (len > 0)
{
int sz = Math.Min(len, b2.Length);
arcfour.EncryptARCFOUR(b, off, sz, b2, 0);
outc.Write(b2, 0, sz);
len -= sz;
off += sz;
}
}
}
public virtual byte[] Update(byte[] b, int off, int len)
{
byte[] b2 = new byte[len];
arcfour.EncryptARCFOUR(b, off, len, b2, 0);
return(b2);
}
