public byte[] Update(byte[] b, int off, int len) {
if (aes) {
if (initiated)
return cipher.Update(b, off, len);
else {
int left = Math.Min(iv.Length - ivptr, len);
System.Array.Copy(b, off, iv, ivptr, left);
off += left;
len -= left;
ivptr += left;
if (ivptr == iv.Length) {
cipher = new AESCipher(false, key, iv);
initiated = true;
if (len > 0)
return cipher.Update(b, off, len);
}
return null;
}
}
else {
byte[] b2 = new byte[len];
arcfour.EncryptARCFOUR(b, off, len, b2, 0);
return b2;
}
}
public byte[] Update(byte[] b, int off, int len)
{
if (aes)
{
if (initiated)
{
return(cipher.Update(b, off, len));
}
else
{
int left = Math.Min(iv.Length - ivptr, len);
System.Array.Copy(b, off, iv, ivptr, left);
off += left;
len -= left;
ivptr += left;
if (ivptr == iv.Length)
{
cipher = new AESCipher(false, key, iv);
initiated = true;
if (len > 0)
{
return(cipher.Update(b, off, len));
}
}
return(null);
}
}
else
{
byte[] b2 = new byte[len];
arcfour.EncryptARCFOUR(b, off, len, b2, 0);
return(b2);
}
}
public OutputStreamEncryption(Stream outc, byte[] key, int off, int len, int revision) {
this.outc = outc;
aes = revision == AES_128;
if (aes) {
byte[] iv = IVGenerator.GetIV();
byte[] nkey = new byte[len];
System.Array.Copy(key, off, nkey, 0, len);
cipher = new AESCipher(true, nkey, iv);
Write(iv, 0, iv.Length);
}
else {
arcfour = new ARCFOUREncryption();
arcfour.PrepareARCFOURKey(key, off, len);
}
}
