// 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};

  std::memcpy(pbox, p_init, sizeof(p_init));

  std::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