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jellyfin/Emby.Common.Implementations/IO/SharpCifs/Util/RC4.cs

69 lines
1.7 KiB

// This code is derived from jcifs smb client library <jcifs at samba dot org>
// Ported by J. Arturo <webmaster at komodosoft dot net>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
namespace SharpCifs.Util
{
public class Rc4
{
internal byte[] S;
internal int I;
internal int J;
public Rc4()
{
}
public Rc4(byte[] key)
{
Init(key, 0, key.Length);
}
public virtual void Init(byte[] key, int ki, int klen)
{
S = new byte[256];
for (I = 0; I < 256; I++)
{
S[I] = unchecked((byte)I);
}
for (I = J = 0; I < 256; I++)
{
J = (J + key[ki + I % klen] + S[I]) & unchecked(0xff);
byte t = S[I];
S[I] = S[J];
S[J] = t;
}
I = J = 0;
}
public virtual void Update(byte[] src, int soff, int slen, byte[] dst, int doff)
{
int slim;
slim = soff + slen;
while (soff < slim)
{
I = (I + 1) & unchecked(0xff);
J = (J + S[I]) & unchecked(0xff);
byte t = S[I];
S[I] = S[J];
S[J] = t;
dst[doff++] = unchecked((byte)(src[soff++] ^ S[(S[I] + S[J]) & unchecked(0xff)]));
}
}
}
}