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rc4.c

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  • Forked from Nettle / nettle
    4751 commits behind the upstream repository.
    • Niels Möller's avatar
      2ed0c4b5
      Hacked configure scripts, makefiles and crypto_types.h. · 2ed0c4b5
      Niels Möller authored
      Rev: src/symmetric/Makefile.in:1.2
      Rev: src/symmetric/cast.c:1.2
      Rev: src/symmetric/configure.in:1.2
      Rev: src/symmetric/desCode.h:1.2
      Rev: src/symmetric/desKerb.c:1.2
      Rev: src/symmetric/desQuick.c:1.2
      Rev: src/symmetric/desUtil.c:1.2
      Rev: src/symmetric/desdata.c:1.2
      Rev: src/symmetric/idea.c:1.2
      Rev: src/symmetric/include/cast.h:1.2
      Rev: src/symmetric/include/crypto_types.h:1.2
      Rev: src/symmetric/include/des.h:1.2
      Rev: src/symmetric/include/idea.h:1.2
      Rev: src/symmetric/include/md5.h:1.2
      Rev: src/symmetric/include/rc4.h:1.2
      Rev: src/symmetric/include/sha.h:1.2
      Rev: src/symmetric/md5.c:1.2
      Rev: src/symmetric/rc4.c:1.2
      Rev: src/symmetric/sha.c:1.2
      2ed0c4b5
      History
      Hacked configure scripts, makefiles and crypto_types.h.
      Niels Möller authored
      Rev: src/symmetric/Makefile.in:1.2
      Rev: src/symmetric/cast.c:1.2
      Rev: src/symmetric/configure.in:1.2
      Rev: src/symmetric/desCode.h:1.2
      Rev: src/symmetric/desKerb.c:1.2
      Rev: src/symmetric/desQuick.c:1.2
      Rev: src/symmetric/desUtil.c:1.2
      Rev: src/symmetric/desdata.c:1.2
      Rev: src/symmetric/idea.c:1.2
      Rev: src/symmetric/include/cast.h:1.2
      Rev: src/symmetric/include/crypto_types.h:1.2
      Rev: src/symmetric/include/des.h:1.2
      Rev: src/symmetric/include/idea.h:1.2
      Rev: src/symmetric/include/md5.h:1.2
      Rev: src/symmetric/include/rc4.h:1.2
      Rev: src/symmetric/include/sha.h:1.2
      Rev: src/symmetric/md5.c:1.2
      Rev: src/symmetric/rc4.c:1.2
      Rev: src/symmetric/sha.c:1.2
    rc4.c 952 B
    /* rc4.c
     *
     */
    
    #include "crypto_types.h"
    #include <rc4.h>
    
    #ifdef RCSID
    RCSID("$Id$");
    #endif
    
    #define SWAP(a,b) do { int _t = a; a = b; b = _t; } while(0)
    
    void rc4_set_key(struct rc4_ctx *ctx, const UINT8 *key, UINT32 len)
    {
      register UINT8 j; /* Depends on the eight-bitness of these variables. */
      unsigned i;
      UINT32 k;
    
      /* Initialize context */
      i = 0;
      do ctx->S[i] = i; while (++i < 256);
    
      /* Expand key */
      i = j = k = 0;
      do {
        j += ctx->S[i] + key[k];
        SWAP(ctx->S[i], ctx->S[j]);
        k = (k+1) % len; /* Repeat key if needed */
      } while(++i < 256);
      
      ctx->i = ctx->j = 0;
    }
    
    void rc4_crypt(struct rc4_ctx *ctx, UINT8 *dest, const UINT8 *src, UINT32 len)
    {
      register UINT8 i, j;
    
      i = ctx->i; j = ctx->j;
      while(len--)
        {
          i++; i &= 0xff;
          j += ctx->S[i]; j &= 0xff;
          SWAP(ctx->S[i], ctx->S[j]);
          *dest++ = *src++ ^ ctx->S[ (ctx->S[i] + ctx->S[j]) & 0xff ];
        }
      ctx->i = i; ctx->j = j;
    }