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aes_ige.c
/* crypto/aes/aes_ige.c -*- mode:C; c-file-style: "eay" -*- */
/* ====================================================================
 * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 */

#include "cryptlib.h"

#include <openssl/aes.h>
#include "aes_locl.h"

#define N_WORDS (AES_BLOCK_SIZE / sizeof(unsigned long))
00058 typedef struct {
        unsigned long data[N_WORDS];
} aes_block_t;

/* XXX: probably some better way to do this */
#if defined(__i386__) || defined(__x86_64__)
#define UNALIGNED_MEMOPS_ARE_FAST 1
#else
#define UNALIGNED_MEMOPS_ARE_FAST 0
#endif

#if UNALIGNED_MEMOPS_ARE_FAST
#define load_block(d, s)        (d) = *(const aes_block_t *)(s)
#define store_block(d, s)       *(aes_block_t *)(d) = (s)
#else
#define load_block(d, s)        memcpy((d).data, (s), AES_BLOCK_SIZE)
#define store_block(d, s)       memcpy((d), (s).data, AES_BLOCK_SIZE)
#endif

/* N.B. The IV for this mode is _twice_ the block size */

void AES_ige_encrypt(const unsigned char *in, unsigned char *out,
                               size_t length, const AES_KEY *key,
                               unsigned char *ivec, const int enc)
      {
      size_t n;
      size_t len = length;

      OPENSSL_assert(in && out && key && ivec);
      OPENSSL_assert((AES_ENCRYPT == enc)||(AES_DECRYPT == enc));
      OPENSSL_assert((length%AES_BLOCK_SIZE) == 0);

      len = length / AES_BLOCK_SIZE;

      if (AES_ENCRYPT == enc)
            {
            if (in != out &&
                (UNALIGNED_MEMOPS_ARE_FAST || ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(long)==0))
                  {
                  aes_block_t *ivp = (aes_block_t *)ivec;
                  aes_block_t *iv2p = (aes_block_t *)(ivec + AES_BLOCK_SIZE);

                  while (len)
                        {
                        aes_block_t *inp = (aes_block_t *)in;
                        aes_block_t *outp = (aes_block_t *)out;

                        for(n=0 ; n < N_WORDS; ++n)
                              outp->data[n] = inp->data[n] ^ ivp->data[n];
                        AES_encrypt((unsigned char *)outp->data, (unsigned char *)outp->data, key);
                        for(n=0 ; n < N_WORDS; ++n)
                              outp->data[n] ^= iv2p->data[n];
                        ivp = outp;
                        iv2p = inp;
                        --len;
                        in += AES_BLOCK_SIZE;
                        out += AES_BLOCK_SIZE;
                        }
                  memcpy(ivec, ivp->data, AES_BLOCK_SIZE);
                  memcpy(ivec + AES_BLOCK_SIZE, iv2p->data, AES_BLOCK_SIZE);
                  }
            else
                  {
                  aes_block_t tmp, tmp2;
                  aes_block_t iv;
                  aes_block_t iv2;

                  load_block(iv, ivec);
                  load_block(iv2, ivec + AES_BLOCK_SIZE);

                  while (len)
                        {
                        load_block(tmp, in);
                        for(n=0 ; n < N_WORDS; ++n)
                              tmp2.data[n] = tmp.data[n] ^ iv.data[n];
                        AES_encrypt((unsigned char *)tmp2.data, (unsigned char *)tmp2.data, key);
                        for(n=0 ; n < N_WORDS; ++n)
                              tmp2.data[n] ^= iv2.data[n];
                        store_block(out, tmp2);
                        iv = tmp2;
                        iv2 = tmp;
                        --len;
                        in += AES_BLOCK_SIZE;
                        out += AES_BLOCK_SIZE;
                        }
                  memcpy(ivec, iv.data, AES_BLOCK_SIZE);
                  memcpy(ivec + AES_BLOCK_SIZE, iv2.data, AES_BLOCK_SIZE);
                  }
            }
      else
            {
            if (in != out &&
                (UNALIGNED_MEMOPS_ARE_FAST || ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(long)==0))
                  {
                  aes_block_t *ivp = (aes_block_t *)ivec;
                  aes_block_t *iv2p = (aes_block_t *)(ivec + AES_BLOCK_SIZE);

                  while (len)
                        {
                        aes_block_t tmp;
                        aes_block_t *inp = (aes_block_t *)in;
                        aes_block_t *outp = (aes_block_t *)out;

                        for(n=0 ; n < N_WORDS; ++n)
                              tmp.data[n] = inp->data[n] ^ iv2p->data[n];
                        AES_decrypt((unsigned char *)tmp.data, (unsigned char *)outp->data, key);
                        for(n=0 ; n < N_WORDS; ++n)
                              outp->data[n] ^= ivp->data[n];
                        ivp = inp;
                        iv2p = outp;
                        --len;
                        in += AES_BLOCK_SIZE;
                        out += AES_BLOCK_SIZE;
                        }
                  memcpy(ivec, ivp->data, AES_BLOCK_SIZE);
                  memcpy(ivec + AES_BLOCK_SIZE, iv2p->data, AES_BLOCK_SIZE);
                  }
            else
                  {
                  aes_block_t tmp, tmp2;
                  aes_block_t iv;
                  aes_block_t iv2;

                  load_block(iv, ivec);
                  load_block(iv2, ivec + AES_BLOCK_SIZE);

                  while (len)
                        {
                        load_block(tmp, in);
                        tmp2 = tmp;
                        for(n=0 ; n < N_WORDS; ++n)
                              tmp.data[n] ^= iv2.data[n];
                        AES_decrypt((unsigned char *)tmp.data, (unsigned char *)tmp.data, key);
                        for(n=0 ; n < N_WORDS; ++n)
                              tmp.data[n] ^= iv.data[n];
                        store_block(out, tmp);
                        iv = tmp2;
                        iv2 = tmp;
                        --len;
                        in += AES_BLOCK_SIZE;
                        out += AES_BLOCK_SIZE;
                        }
                  memcpy(ivec, iv.data, AES_BLOCK_SIZE);
                  memcpy(ivec + AES_BLOCK_SIZE, iv2.data, AES_BLOCK_SIZE);
                  }
            }
      }

/*
 * Note that its effectively impossible to do biIGE in anything other
 * than a single pass, so no provision is made for chaining.
 */

/* N.B. The IV for this mode is _four times_ the block size */

void AES_bi_ige_encrypt(const unsigned char *in, unsigned char *out,
                                    size_t length, const AES_KEY *key,
                                    const AES_KEY *key2, const unsigned char *ivec,
                                    const int enc)
      {
      size_t n;
      size_t len = length;
      unsigned char tmp[AES_BLOCK_SIZE];
      unsigned char tmp2[AES_BLOCK_SIZE];
      unsigned char tmp3[AES_BLOCK_SIZE];
      unsigned char prev[AES_BLOCK_SIZE];
      const unsigned char *iv;
      const unsigned char *iv2;

      OPENSSL_assert(in && out && key && ivec);
      OPENSSL_assert((AES_ENCRYPT == enc)||(AES_DECRYPT == enc));
      OPENSSL_assert((length%AES_BLOCK_SIZE) == 0);

      if (AES_ENCRYPT == enc)
            {
            /* XXX: Do a separate case for when in != out (strictly should
               check for overlap, too) */

            /* First the forward pass */ 
            iv = ivec;
            iv2 = ivec + AES_BLOCK_SIZE;
            while (len >= AES_BLOCK_SIZE)
                  {
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        out[n] = in[n] ^ iv[n];
                  AES_encrypt(out, out, key);
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        out[n] ^= iv2[n];
                  iv = out;
                  memcpy(prev, in, AES_BLOCK_SIZE);
                  iv2 = prev;
                  len -= AES_BLOCK_SIZE;
                  in += AES_BLOCK_SIZE;
                  out += AES_BLOCK_SIZE;
                  }

            /* And now backwards */
            iv = ivec + AES_BLOCK_SIZE*2;
            iv2 = ivec + AES_BLOCK_SIZE*3;
            len = length;
            while(len >= AES_BLOCK_SIZE)
                  {
                  out -= AES_BLOCK_SIZE;
                  /* XXX: reduce copies by alternating between buffers */
                  memcpy(tmp, out, AES_BLOCK_SIZE);
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        out[n] ^= iv[n];
                  /*                hexdump(stdout, "out ^ iv", out, AES_BLOCK_SIZE); */
                  AES_encrypt(out, out, key);
                  /*                hexdump(stdout,"enc", out, AES_BLOCK_SIZE); */
                  /*                hexdump(stdout,"iv2", iv2, AES_BLOCK_SIZE); */
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        out[n] ^= iv2[n];
                  /*                hexdump(stdout,"out", out, AES_BLOCK_SIZE); */
                  iv = out;
                  memcpy(prev, tmp, AES_BLOCK_SIZE);
                  iv2 = prev;
                  len -= AES_BLOCK_SIZE;
                  }
            }
      else
            {
            /* First backwards */
            iv = ivec + AES_BLOCK_SIZE*2;
            iv2 = ivec + AES_BLOCK_SIZE*3;
            in += length;
            out += length;
            while (len >= AES_BLOCK_SIZE)
                  {
                  in -= AES_BLOCK_SIZE;
                  out -= AES_BLOCK_SIZE;
                  memcpy(tmp, in, AES_BLOCK_SIZE);
                  memcpy(tmp2, in, AES_BLOCK_SIZE);
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        tmp[n] ^= iv2[n];
                  AES_decrypt(tmp, out, key);
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        out[n] ^= iv[n];
                  memcpy(tmp3, tmp2, AES_BLOCK_SIZE);
                  iv = tmp3;
                  iv2 = out;
                  len -= AES_BLOCK_SIZE;
                  }

            /* And now forwards */
            iv = ivec;
            iv2 = ivec + AES_BLOCK_SIZE;
            len = length;
            while (len >= AES_BLOCK_SIZE)
                  {
                  memcpy(tmp, out, AES_BLOCK_SIZE);
                  memcpy(tmp2, out, AES_BLOCK_SIZE);
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        tmp[n] ^= iv2[n];
                  AES_decrypt(tmp, out, key);
                  for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
                        out[n] ^= iv[n];
                  memcpy(tmp3, tmp2, AES_BLOCK_SIZE);
                  iv = tmp3;
                  iv2 = out;
                  len -= AES_BLOCK_SIZE;
                  in += AES_BLOCK_SIZE;
                  out += AES_BLOCK_SIZE;
                  }
            }
      }

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