/*

 * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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 "des_local.h"

/*

 * The input and output encrypted as though 64bit cfb mode is being used.

 * The extra state information to record how much of the 64bit block we have

 * used is contained in *num;

 */

void DES_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out,

                            long length, DES_key_schedule *ks1,

                            DES_key_schedule *ks2, DES_key_schedule *ks3,

                            DES_cblock *ivec, int *num, int enc)

{

    register DES_LONG v0, v1;

    register long l = length;

    register int n = *num;

    DES_LONG ti[2];

    unsigned char *iv, c, cc;

    iv = &(*ivec)[0];

    if (enc) {

        while (l--) {

            if (n == 0) {

                c2l(iv, v0);

                c2l(iv, v1);

                ti[0] = v0;

                ti[1] = v1;

                DES_encrypt3(ti, ks1, ks2, ks3);

                v0 = ti[0];

                v1 = ti[1];

                iv = &(*ivec)[0];

                l2c(v0, iv);

                l2c(v1, iv);

                iv = &(*ivec)[0];

            }

            c = *(in++) ^ iv[n];

            *(out++) = c;

            iv[n] = c;

            n = (n + 1) & 0x07;

        }

    } else {

        while (l--) {

            if (n == 0) {

                c2l(iv, v0);

                c2l(iv, v1);

                ti[0] = v0;

                ti[1] = v1;

                DES_encrypt3(ti, ks1, ks2, ks3);

                v0 = ti[0];

                v1 = ti[1];

                iv = &(*ivec)[0];

                l2c(v0, iv);

                l2c(v1, iv);

                iv = &(*ivec)[0];

            }

            cc = *(in++);

            c = iv[n];

            iv[n] = cc;

            *(out++) = c ^ cc;

            n = (n + 1) & 0x07;

        }

    }

    v0 = v1 = ti[0] = ti[1] = c = cc = 0;

    *num = n;

}

/*

 * This is compatible with the single key CFB-r for DES, even thought that's

 * not what EVP needs.

 */

void DES_ede3_cfb_encrypt(const unsigned char *in, unsigned char *out,

                          int numbits, long length, DES_key_schedule *ks1,

                          DES_key_schedule *ks2, DES_key_schedule *ks3,

                          DES_cblock *ivec, int enc)

{

    register DES_LONG d0, d1, v0, v1;

    register unsigned long l = length, n = ((unsigned int)numbits + 7) / 8;

    register int num = numbits, i;

    DES_LONG ti[2];

    unsigned char *iv;

    unsigned char ovec[16];

    if (num > 64)

        return;

    iv = &(*ivec)[0];

    c2l(iv, v0);

    c2l(iv, v1);

    if (enc) {

        while (l >= n) {

            l -= n;

            ti[0] = v0;

            ti[1] = v1;

            DES_encrypt3(ti, ks1, ks2, ks3);

            c2ln(in, d0, d1, n);

            in += n;

            d0 ^= ti[0];

            d1 ^= ti[1];

            l2cn(d0, d1, out, n);

            out += n;

            /*

             * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under

             * gcc :-(

             */

            if (num == 32) {

                v0 = v1;

                v1 = d0;

            } else if (num == 64) {

                v0 = d0;

                v1 = d1;

            } else {

                iv = &ovec[0];

                l2c(v0, iv);

                l2c(v1, iv);

                l2c(d0, iv);

                l2c(d1, iv);

                /* shift ovec left most of the bits... */

                memmove(ovec, ovec + num / 8, 8 + (num % 8 ? 1 : 0));

                /* now the remaining bits */

                if (num % 8 != 0)

                    for (i = 0; i < 8; ++i) {

                        ovec[i] <<= num % 8;

                        ovec[i] |= ovec[i + 1] >> (8 - num % 8);

                    }

                iv = &ovec[0];

                c2l(iv, v0);

                c2l(iv, v1);

            }

        }

    } else {

        while (l >= n) {

            l -= n;

            ti[0] = v0;

            ti[1] = v1;

            DES_encrypt3(ti, ks1, ks2, ks3);

            c2ln(in, d0, d1, n);

            in += n;

            /*

             * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under

             * gcc :-(

             */

            if (num == 32) {

                v0 = v1;

                v1 = d0;

            } else if (num == 64) {

                v0 = d0;

                v1 = d1;

            } else {

                iv = &ovec[0];

                l2c(v0, iv);

                l2c(v1, iv);

                l2c(d0, iv);

                l2c(d1, iv);

                /* shift ovec left most of the bits... */

                memmove(ovec, ovec + num / 8, 8 + (num % 8 ? 1 : 0));

                /* now the remaining bits */

                if (num % 8 != 0)

                    for (i = 0; i < 8; ++i) {

                        ovec[i] <<= num % 8;

                        ovec[i] |= ovec[i + 1] >> (8 - num % 8);

                    }

                iv = &ovec[0];

                c2l(iv, v0);

                c2l(iv, v1);

            }

            d0 ^= ti[0];

            d1 ^= ti[1];

            l2cn(d0, d1, out, n);

            out += n;

        }

    }

    iv = &(*ivec)[0];

    l2c(v0, iv);

    l2c(v1, iv);

    v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0;

}