blowfish.cpp

// blowfish.cpp - originally written and placed in the public domain by Wei Dai
 
#include "pch.h"
#include "blowfish.h"
#include "misc.h"
 
NAMESPACE_BEGIN(CryptoPP)
 
void Blowfish::Base::UncheckedSetKey(const byte *key_string, unsigned int keylength, const NameValuePairs &)
{
        AssertValidKeyLength(keylength);
 
        unsigned i, j=0, k;
        word32 data, dspace[2] = {0, 0};
 
        memcpy(pbox, p_init, sizeof(p_init));
        memcpy(sbox, s_init, sizeof(s_init));
 
        // Xor key string into encryption key vector
        for (i=0 ; i<ROUNDS+2 ; ++i)
        {
                data = 0 ;
                for (k=0 ; k<4 ; ++k )
                        data = (data << 8) | key_string[j++ % keylength];
                pbox[i] ^= data;
        }
 
        crypt_block(dspace, pbox);
 
        for (i=0; i<ROUNDS; i+=2)
                crypt_block(pbox+i, pbox+i+2);
 
        crypt_block(pbox+ROUNDS, sbox);
 
        for (i=0; i<4*256-2; i+=2)
                crypt_block(sbox+i, sbox+i+2);
 
        if (!IsForwardTransformation())
                for (i=0; i<(ROUNDS+2)/2; i++)
                        std::swap(pbox[i], pbox[ROUNDS+1-i]);
}
 
// this version is only used to make pbox and sbox
void Blowfish::Base::crypt_block(const word32 in[2], word32 out[2]) const
{
        word32 left = in[0];
        word32 right = in[1];
 
        const word32 *const s=sbox;
        const word32 *p=pbox;
 
        left ^= p[0];
 
        for (unsigned i=0; i<ROUNDS/2; i++)
        {
                right ^= (((s[GETBYTE(left,3)] + s[256+GETBYTE(left,2)])
                          ^ s[2*256+GETBYTE(left,1)]) + s[3*256+GETBYTE(left,0)])
                          ^ p[2*i+1];
 
                left ^= (((s[GETBYTE(right,3)] + s[256+GETBYTE(right,2)])
                         ^ s[2*256+GETBYTE(right,1)]) + s[3*256+GETBYTE(right,0)])
                         ^ p[2*i+2];
        }
 
        right ^= p[ROUNDS+1];
 
        out[0] = right;
        out[1] = left;
}
 
void Blowfish::Base::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
        typedef BlockGetAndPut<word32, BigEndian> Block;
 
        word32 left, right;
        Block::Get(inBlock)(left)(right);
 
        const word32 *const s=sbox;
        const word32 *p=pbox;
 
        left ^= p[0];
 
        for (unsigned i=0; i<ROUNDS/2; i++)
        {
                right ^= (((s[GETBYTE(left,3)] + s[256+GETBYTE(left,2)])
                          ^ s[2*256+GETBYTE(left,1)]) + s[3*256+GETBYTE(left,0)])
                          ^ p[2*i+1];
 
                left ^= (((s[GETBYTE(right,3)] + s[256+GETBYTE(right,2)])
                         ^ s[2*256+GETBYTE(right,1)]) + s[3*256+GETBYTE(right,0)])
                         ^ p[2*i+2];
        }
 
        right ^= p[ROUNDS+1];
 
        Block::Put(xorBlock, outBlock)(right)(left);
}
 
NAMESPACE_END