www.pudn.com > sslref30.zip > cbc_enc.c

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