/*
 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <openssl/blowfish.h>
#include "bf_local.h"

/*
 * Blowfish as implemented from 'Blowfish: Springer-Verlag paper' (From
 * LECTURE NOTES IN COMPUTER SCIENCE 809, FAST SOFTWARE ENCRYPTION, CAMBRIDGE
 * SECURITY WORKSHOP, CAMBRIDGE, U.K., DECEMBER 9-11, 1993)
 */

#if (BF_ROUNDS != 16) && (BF_ROUNDS != 20)
# error If you set BF_ROUNDS to some value other than 16 or 20, you will have \
to modify the code.
#endif

void BF_encrypt(BF_LONG *data, const BF_KEY *key)
{
    register BF_LONG l, r;
    register const BF_LONG *p, *s;

    p = key->P;
    s = &(key->S[0]);
    l = data[0];
    r = data[1];

    l ^= p[0];
    BF_ENC(r, l, s, p[1]);
    BF_ENC(l, r, s, p[2]);
    BF_ENC(r, l, s, p[3]);
    BF_ENC(l, r, s, p[4]);
    BF_ENC(r, l, s, p[5]);
    BF_ENC(l, r, s, p[6]);
    BF_ENC(r, l, s, p[7]);
    BF_ENC(l, r, s, p[8]);
    BF_ENC(r, l, s, p[9]);
    BF_ENC(l, r, s, p[10]);
    BF_ENC(r, l, s, p[11]);
    BF_ENC(l, r, s, p[12]);
    BF_ENC(r, l, s, p[13]);
    BF_ENC(l, r, s, p[14]);
    BF_ENC(r, l, s, p[15]);
    BF_ENC(l, r, s, p[16]);
# if BF_ROUNDS == 20
    BF_ENC(r, l, s, p[17]);
    BF_ENC(l, r, s, p[18]);
    BF_ENC(r, l, s, p[19]);
    BF_ENC(l, r, s, p[20]);
# endif
    r ^= p[BF_ROUNDS + 1];

    data[1] = l & 0xffffffffU;
    data[0] = r & 0xffffffffU;
}

void BF_decrypt(BF_LONG *data, const BF_KEY *key)
{
    register BF_LONG l, r;
    register const BF_LONG *p, *s;

    p = key->P;
    s = &(key->S[0]);
    l = data[0];
    r = data[1];

    l ^= p[BF_ROUNDS + 1];
#  if BF_ROUNDS == 20
    BF_ENC(r, l, s, p[20]);
    BF_ENC(l, r, s, p[19]);
    BF_ENC(r, l, s, p[18]);
    BF_ENC(l, r, s, p[17]);
#  endif
    BF_ENC(r, l, s, p[16]);
    BF_ENC(l, r, s, p[15]);
    BF_ENC(r, l, s, p[14]);
    BF_ENC(l, r, s, p[13]);
    BF_ENC(r, l, s, p[12]);
    BF_ENC(l, r, s, p[11]);
    BF_ENC(r, l, s, p[10]);
    BF_ENC(l, r, s, p[9]);
    BF_ENC(r, l, s, p[8]);
    BF_ENC(l, r, s, p[7]);
    BF_ENC(r, l, s, p[6]);
    BF_ENC(l, r, s, p[5]);
    BF_ENC(r, l, s, p[4]);
    BF_ENC(l, r, s, p[3]);
    BF_ENC(r, l, s, p[2]);
    BF_ENC(l, r, s, p[1]);
    r ^= p[0];

    data[1] = l & 0xffffffffU;
    data[0] = r & 0xffffffffU;
}

void BF_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
                    const BF_KEY *schedule, unsigned char *ivec, int encrypt)
{
    register BF_LONG tin0, tin1;
    register BF_LONG tout0, tout1, xor0, xor1;
    register long l = length;
    BF_LONG tin[2];

    if (encrypt) {
        n2l(ivec, tout0);
        n2l(ivec, tout1);
        ivec -= 8;
        for (l -= 8; l >= 0; l -= 8) {
            n2l(in, tin0);
            n2l(in, tin1);
            tin0 ^= tout0;
            tin1 ^= tout1;
            tin[0] = tin0;
            tin[1] = tin1;
            BF_encrypt(tin, schedule);
            tout0 = tin[0];
            tout1 = tin[1];
            l2n(tout0, out);
            l2n(tout1, out);
        }
        if (l != -8) {
            n2ln(in, tin0, tin1, l + 8);
            tin0 ^= tout0;
            tin1 ^= tout1;
            tin[0] = tin0;
            tin[1] = tin1;
            BF_encrypt(tin, schedule);
            tout0 = tin[0];
            tout1 = tin[1];
            l2n(tout0, out);
            l2n(tout1, out);
        }
        l2n(tout0, ivec);
        l2n(tout1, ivec);
    } else {
        n2l(ivec, xor0);
        n2l(ivec, xor1);
        ivec -= 8;
        for (l -= 8; l >= 0; l -= 8) {
            n2l(in, tin0);
            n2l(in, tin1);
            tin[0] = tin0;
            tin[1] = tin1;
            BF_decrypt(tin, schedule);
            tout0 = tin[0] ^ xor0;
            tout1 = tin[1] ^ xor1;
            l2n(tout0, out);
            l2n(tout1, out);
            xor0 = tin0;
            xor1 = tin1;
        }
        if (l != -8) {
            n2l(in, tin0);
            n2l(in, tin1);
            tin[0] = tin0;
            tin[1] = tin1;
            BF_decrypt(tin, schedule);
            tout0 = tin[0] ^ xor0;
            tout1 = tin[1] ^ xor1;
            l2nn(tout0, tout1, out, l + 8);
            xor0 = tin0;
            xor1 = tin1;
        }
        l2n(xor0, ivec);
        l2n(xor1, ivec);
    }
    tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
    tin[0] = tin[1] = 0;
}