50 lines
1.5 KiB
C#
50 lines
1.5 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
using System.Linq;
|
|
using System.Text;
|
|
using System.Threading.Tasks;
|
|
using System.Numerics;
|
|
using Glove;
|
|
|
|
namespace SockScape.Encryption {
|
|
class StreamCipher {
|
|
private readonly byte[] Key = new byte[Encryption.Key.KeySizeBytes];
|
|
private readonly byte[] State = new byte[256];
|
|
|
|
public StreamCipher(BigInteger key) {
|
|
int i = 0, j = 0;
|
|
State = State.Select(x => (byte)i++).ToArray();
|
|
Key = Key.Select(x => (byte)0).ToArray();
|
|
Array.Copy(key.ToByteArray(), Key, Key.Length);
|
|
|
|
for(i = 0; i < State.Length; ++i) {
|
|
j = (j + State[i] + Key[i % Key.Length]) % 256;
|
|
Utils.Swap(ref State[i], ref State[j]);
|
|
}
|
|
|
|
GenerateStream(1024);
|
|
}
|
|
|
|
private byte[] GenerateStream(long length) {
|
|
var stream = new byte[length];
|
|
int i = 0, j = 0;
|
|
|
|
for(long x = 0; x < length; ++x) {
|
|
i = (i + 1) % 256;
|
|
j = (j + State[i]) % 256;
|
|
Utils.Swap(ref State[i], ref State[j]);
|
|
stream[x] = State[(State[i] + State[j]) % 256];
|
|
}
|
|
|
|
return stream;
|
|
}
|
|
|
|
public byte[] Parse(byte[] data) {
|
|
var stream = GenerateStream(data.LongLength);
|
|
for(long i = 0; i < data.LongLength; ++i)
|
|
data[i] ^= stream[i];
|
|
|
|
return data;
|
|
}
|
|
}
|
|
}
|