84 lines
1.5 KiB
C
84 lines
1.5 KiB
C
/* cbc_enc.c */
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/* Copyright (C) 1993 Eric Young - see README for more details */
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/*-
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* $Id: cbc_enc.c,v 1.2 1994/07/19 19:21:47 g89r4222 Exp $
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*/
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#include "des_locl.h"
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int des_cbc_encrypt(input,output,length,schedule,ivec,encrypt)
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des_cblock *input;
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des_cblock *output;
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long length;
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des_key_schedule schedule;
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des_cblock *ivec;
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int encrypt;
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{
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register unsigned long tin0,tin1;
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register unsigned long tout0,tout1,xor0,xor1;
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register unsigned char *in,*out;
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register long l=length;
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unsigned long tout[2],tin[2];
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unsigned char *iv;
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in=(unsigned char *)input;
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out=(unsigned char *)output;
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iv=(unsigned char *)ivec;
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if (encrypt)
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{
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c2l(iv,tout0);
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c2l(iv,tout1);
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for (; l>0; l-=8)
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{
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if (l >= 8)
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{
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c2l(in,tin0);
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c2l(in,tin1);
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}
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else
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c2ln(in,tin0,tin1,l);
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tin0^=tout0;
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tin1^=tout1;
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tin[0]=tin0;
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tin[1]=tin1;
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des_encrypt((unsigned long *)tin,(unsigned long *)tout,
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schedule,encrypt);
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tout0=tout[0];
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tout1=tout[1];
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l2c(tout0,out);
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l2c(tout1,out);
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}
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}
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else
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{
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c2l(iv,xor0);
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c2l(iv,xor1);
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for (; l>0; l-=8)
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{
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c2l(in,tin0);
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c2l(in,tin1);
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tin[0]=tin0;
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tin[1]=tin1;
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des_encrypt((unsigned long *)tin,(unsigned long *)tout,
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schedule,encrypt);
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tout0=tout[0]^xor0;
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tout1=tout[1]^xor1;
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if (l >= 8)
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{
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l2c(tout0,out);
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l2c(tout1,out);
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}
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else
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l2cn(tout0,tout1,out,l);
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xor0=tin0;
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xor1=tin1;
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}
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}
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tin0=tin1=tout0=tout1=xor0=xor1=0;
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tin[0]=tin[1]=tout[0]=tout[1]=0;
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return(0);
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}
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