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/*
ARCFOUR cipher (based on a cipher posted on the Usenet in Spring-95).
This cipher is widely believed and has been tested to be equivalent
with the RC4 cipher from RSA Data Security, Inc. (RC4 is a trademark
of RSA Data Security)
*/
/*
* $Id: arcfour.c,v 1.1.1.1 1996/02/18 21:38:11 ylo Exp $
* $Log: arcfour.c,v $
* Revision 1.1.1.1 1996/02/18 21:38:11 ylo
* Imported ssh-1.2.13.
*
* Revision 1.2 1995/07/13 01:29:59 ylo
* Added cvs log.
*
* $Endlog$
*/
#include "includes.h"
#include "arcfour.h"
void arcfour_init(ArcfourContext *ctx, const unsigned char *key,
unsigned int key_len)
{
unsigned int t, u;
unsigned int keyindex;
unsigned int stateindex;
unsigned char* state;
unsigned int counter;
assert(key_len > 0);
state = &ctx->state[0];
ctx->x = 0;
ctx->y = 0;
for (counter = 0; counter < 256; counter++)
state[counter] = counter;
keyindex = 0;
stateindex = 0;
for (counter = 0; counter < 256; counter++)
{
t = state[counter];
stateindex = (stateindex + key[keyindex] + t) & 0xff;
u = state[stateindex];
state[stateindex] = t;
state[counter] = u;
if (++keyindex >= key_len)
keyindex = 0;
}
}
inline unsigned int arcfour_byte(ArcfourContext *ctx)
{
unsigned int x;
unsigned int y;
unsigned int sx, sy;
unsigned char *state;
state = ctx->state;
x = (ctx->x + 1) & 0xff;
sx = state[x];
y = (sx + ctx->y) & 0xff;
sy = state[y];
ctx->x = x;
ctx->y = y;
state[y] = sx;
state[x] = sy;
return state[(sx + sy) & 0xff];
}
void arcfour_encrypt(ArcfourContext *ctx, unsigned char *dest,
const unsigned char *src, unsigned int len)
{
unsigned int i;
for (i = 0; i < len; i++)
dest[i] = src[i] ^ arcfour_byte(ctx);
}
void arcfour_decrypt(ArcfourContext *ctx, unsigned char *dest,
const unsigned char *src, unsigned int len)
{
arcfour_encrypt(ctx, dest, src, len);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.