source: trunk/src/rijndael-api-fst.c@ 526

/*      $NetBSD: rijndael-api-fst.c,v 1.24 2011/05/14 16:46:55 jmmv Exp $       */

/**
 * rijndael-api-fst.c
 *
 * @version 2.9 (December 2000)
 *
 * Optimised ANSI C code for the Rijndael cipher (now AES)
 *
 * @author Vincent Rijmen <vincent.rijmen@esat.kuleuven.ac.be>
 * @author Antoon Bosselaers <antoon.bosselaers@esat.kuleuven.ac.be>
 * @author Paulo Barreto <paulo.barreto@terra.com.br>
 *
 * This code is hereby placed in the public domain.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS
 * 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 AUTHORS OR 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.
 *
 * Acknowledgements:
 *
 * We are deeply indebted to the following people for their bug reports,
 * fixes, and improvement suggestions to this implementation. Though we
 * tried to list all contributions, we apologise in advance for any
 * missing reference.
 *
 * Andrew Bales <Andrew.Bales@Honeywell.com>
 * Markus Friedl <markus.friedl@informatik.uni-erlangen.de>
 * John Skodon <skodonj@webquill.com>
 */
#include "config_xor.h"

#include <stdlib.h>
#include <string.h>


#ifdef SH_ENCRYPT

#include "rijndael-api-fst.h"

static void xor16(u8 *d, const u8 *a, const u8* b)
{
  size_t i;

        for (i = 0; i < 4; i++) {
                *d++ = *a++ ^ *b++;
                *d++ = *a++ ^ *b++;
                *d++ = *a++ ^ *b++;
                *d++ = *a++ ^ *b++;
        }
}

int
rijndael_makeKey(keyInstance *key, BYTE direction, int keyLen,
    const char *keyMaterial)
{
        u8 cipherKey[RIJNDAEL_MAXKB];
        int i;

        if (key == NULL) {
                return BAD_KEY_INSTANCE;
        }

        if ((direction == DIR_ENCRYPT) || (direction == DIR_DECRYPT)) {
                key->direction = direction;
        } else {
                return BAD_KEY_DIR;
        }

        if ((keyLen == 128) || (keyLen == 192) || (keyLen == 256)) {
                key->keyLen = keyLen;
        } else {
                return BAD_KEY_MAT;
        }

        if (keyMaterial != NULL) {
                char temp[RIJNDAEL_MAX_KEY_SIZE];
                for (i = 0; i < key->keyLen/8; i++) {
                  int t, j;
                  
                  t = *keyMaterial++;
                  if ((t >= '0') && (t <= '9')) j = (t - '0') << 4;
                  else if ((t >= 'a') && (t <= 'f')) j = (t - 'a' + 10) << 4; 
                  else if ((t >= 'A') && (t <= 'F')) j = (t - 'A' + 10) << 4; 
                  else return BAD_KEY_MAT;
                  
                  t = *keyMaterial++;
                  if ((t >= '0') && (t <= '9')) j ^= (t - '0');
                  else if ((t >= 'a') && (t <= 'f')) j ^= (t - 'a' + 10); 
                  else if ((t >= 'A') && (t <= 'F')) j ^= (t - 'A' + 10); 
                  else return BAD_KEY_MAT;
                  
                  temp[i] = (u8)j; 
                }

                /* memcpy(key->keyMaterial, keyMaterial, keyLen/8); */
                memcpy(key->keyMaterial, temp, keyLen/8);
        }

        /* initialize key schedule: */
        memcpy(cipherKey, key->keyMaterial, keyLen/8);
        if (direction == DIR_ENCRYPT) {
                key->Nr = rijndaelKeySetupEnc(key->rk, cipherKey, keyLen);
        } else {
                key->Nr = rijndaelKeySetupDec(key->rk, cipherKey, keyLen);
        }
        rijndaelKeySetupEnc(key->ek, cipherKey, keyLen);
        return TRUE;
}

int
rijndael_cipherInit(cipherInstance *cipher, BYTE mode, const char *IV)
{
        if ((mode == MODE_ECB) || (mode == MODE_CBC) || (mode == MODE_CFB1)) {
                cipher->mode = mode;
        } else {
                return BAD_CIPHER_MODE;
        }
        if (IV != NULL) {
                memcpy(cipher->IV, IV, RIJNDAEL_MAX_IV_SIZE);
        } else {
                memset(cipher->IV, 0, RIJNDAEL_MAX_IV_SIZE);
        }
        return TRUE;
}

int
rijndael_blockEncrypt(cipherInstance *cipher, keyInstance *key,
    const BYTE *input, int inputLen, BYTE *outBuffer)
{
        int i, k, t, numBlocks;
        u8 block[16], *iv;

        if (cipher == NULL ||
                key == NULL ||
                key->direction == DIR_DECRYPT) {
                return BAD_CIPHER_STATE;
        }
        if (input == NULL || inputLen <= 0) {
                return 0; /* nothing to do */
        }

        numBlocks = inputLen/128;

        switch (cipher->mode) {
        case MODE_ECB:
                for (i = numBlocks; i > 0; i--) {
                        rijndaelEncrypt(key->rk, key->Nr, input, outBuffer);
                        input += 16;
                        outBuffer += 16;
                }
                break;

        case MODE_CBC:
                iv = (u8 *)cipher->IV;
                for (i = numBlocks; i > 0; i--) {
                        xor16(block, input, iv);
                        rijndaelEncrypt(key->rk, key->Nr, block, outBuffer);
                        iv = outBuffer;
                        input += 16;
                        outBuffer += 16;
                }
                break;

        case MODE_CFB1:
                iv = (u8 *)cipher->IV;
                for (i = numBlocks; i > 0; i--) {
                        memcpy(outBuffer, input, 16);
                        for (k = 0; k < 128; k++) {
                                rijndaelEncrypt(key->ek, key->Nr, iv, block);
                                outBuffer[k >> 3] ^=
                                    (block[0] & 0x80U) >> (k & 7);
                                for (t = 0; t < 15; t++) {
                                        iv[t] = (iv[t] << 1) | (iv[t + 1] >> 7);
                                }
                                iv[15] = (iv[15] << 1) |
                                    ((outBuffer[k >> 3] >> (7 - (k & 7))) & 1);
                        }
                        outBuffer += 16;
                        input += 16;
                }
                break;

        default:
                return BAD_CIPHER_STATE;
        }

        return 128 * numBlocks;
}

/**
 * Encrypt data partitioned in octets, using RFC 2040-like padding.
 *
 * @param   input           data to be encrypted (octet sequence)
 * @param   inputOctets         input length in octets (not bits)
 * @param   outBuffer       encrypted output data
 *
 * @return      length in octets (not bits) of the encrypted output buffer.
 */
int
rijndael_padEncrypt(cipherInstance *cipher, keyInstance *key,
    const BYTE *input, int inputOctets, BYTE *outBuffer)
{
        int i, numBlocks, padLen;
        u8 block[16], *iv;

        if (cipher == NULL ||
                key == NULL ||
                key->direction == DIR_DECRYPT) {
                return BAD_CIPHER_STATE;
        }
        if (input == NULL || inputOctets <= 0) {
                return 0; /* nothing to do */
        }

        numBlocks = inputOctets / 16;

        switch (cipher->mode) {
        case MODE_ECB:
                for (i = numBlocks; i > 0; i--) {
                        rijndaelEncrypt(key->rk, key->Nr, input, outBuffer);
                        input += 16;
                        outBuffer += 16;
                }
                padLen = 16 - (inputOctets - 16*numBlocks);
                memcpy(block, input, 16 - padLen);
                memset(block + 16 - padLen, padLen, padLen);
                rijndaelEncrypt(key->rk, key->Nr, block, outBuffer);
                break;

        case MODE_CBC:
                iv = (u8 *)cipher->IV;
                for (i = numBlocks; i > 0; i--) {
                        xor16(block, input, iv);
                        rijndaelEncrypt(key->rk, key->Nr, block, outBuffer);
                        iv = outBuffer;
                        input += 16;
                        outBuffer += 16;
                }
                padLen = 16 - (inputOctets - 16*numBlocks);
                for (i = 0; i < 16 - padLen; i++) {
                        block[i] = input[i] ^ iv[i];
                }
                for (i = 16 - padLen; i < 16; i++) {
                        block[i] = (BYTE)padLen ^ iv[i];
                }
                rijndaelEncrypt(key->rk, key->Nr, block, outBuffer);
                break;

        default:
                return BAD_CIPHER_STATE;
        }

        return 16 * (numBlocks + 1);
}

int
rijndael_blockDecrypt(cipherInstance *cipher, keyInstance *key,
    const BYTE *input, int inputLen, BYTE *outBuffer)
{
        int i, k, t, numBlocks;
        u8 block[16], *iv;

        if (cipher == NULL ||
                key == NULL ||
                (cipher->mode != MODE_CFB1 && key->direction == DIR_ENCRYPT)) {
                return BAD_CIPHER_STATE;
        }
        if (input == NULL || inputLen <= 0) {
                return 0; /* nothing to do */
        }

        numBlocks = inputLen/128;

        switch (cipher->mode) {
        case MODE_ECB:
                for (i = numBlocks; i > 0; i--) {
                        rijndaelDecrypt(key->rk, key->Nr, input, outBuffer);
                        input += 16;
                        outBuffer += 16;
                }
                break;

        case MODE_CBC:
                iv = (u8 *)cipher->IV;
                for (i = numBlocks; i > 0; i--) {
                        rijndaelDecrypt(key->rk, key->Nr, input, block);
                        xor16(block, block, iv);
                        if (numBlocks > 1)
                          memcpy(cipher->IV, input, 16);
                        memcpy(outBuffer, block, 16);
                        input += 16;
                        outBuffer += 16;
                }
                break;

    case MODE_CFB1:
                iv = (u8 *)cipher->IV;
                for (i = numBlocks; i > 0; i--) {
                        memcpy(outBuffer, input, 16);
                        for (k = 0; k < 128; k++) {
                                rijndaelEncrypt(key->ek, key->Nr, iv, block);
                                for (t = 0; t < 15; t++) {
                                        iv[t] = (iv[t] << 1) | (iv[t + 1] >> 7);
                                }
                                iv[15] = (iv[15] << 1) |
                                    ((input[k >> 3] >> (7 - (k & 7))) & 1);
                                outBuffer[k >> 3] ^= (block[0] & 0x80U) >>
                                    (k & 7);
                        }
                        outBuffer += 16;
                        input += 16;
                }
                break;

        default:
                return BAD_CIPHER_STATE;
        }

        return 128 * numBlocks;
}

int
rijndael_padDecrypt(cipherInstance *cipher, keyInstance *key,
    const BYTE *input, int inputOctets, BYTE *outBuffer)
{
        int i, numBlocks, padLen;
        u8 block[16], *iv;

        if (cipher == NULL ||
                key == NULL ||
                key->direction == DIR_ENCRYPT) {
                return BAD_CIPHER_STATE;
        }
        if (input == NULL || inputOctets <= 0) {
                return 0; /* nothing to do */
        }
        if (inputOctets % 16 != 0) {
                return BAD_DATA;
        }

        numBlocks = inputOctets/16;

        switch (cipher->mode) {
        case MODE_ECB:
                /* all blocks but last */
                for (i = numBlocks - 1; i > 0; i--) {
                        rijndaelDecrypt(key->rk, key->Nr, input, outBuffer);
                        input += 16;
                        outBuffer += 16;
                }
                /* last block */
                rijndaelDecrypt(key->rk, key->Nr, input, block);
                padLen = block[15];
                if (padLen >= 16) {
                        return BAD_DATA;
                }
                for (i = 16 - padLen; i < 16; i++) {
                        if (block[i] != padLen) {
                                return BAD_DATA;
                        }
                }
                memcpy(outBuffer, block, 16 - padLen);
                break;

        case MODE_CBC:
                iv = (u8 *)cipher->IV;
                /* all blocks but last */
                for (i = numBlocks - 1; i > 0; i--) {
                        rijndaelDecrypt(key->rk, key->Nr, input, block);
                        xor16(block, block, iv);
                        memcpy(cipher->IV, input, 16);
                        memcpy(outBuffer, block, 16);
                        input += 16;
                        outBuffer += 16;
                }
                /* last block */
                rijndaelDecrypt(key->rk, key->Nr, input, block);
                xor16(block, block, iv);
                padLen = block[15];
                if (padLen <= 0 || padLen > 16) {
                        return BAD_DATA;
                }
                for (i = 16 - padLen; i < 16; i++) {
                        if (block[i] != padLen) {
                                return BAD_DATA;
                        }
                }
                memcpy(outBuffer, block, 16 - padLen);
                break;

        default:
                return BAD_CIPHER_STATE;
        }

        return 16 * numBlocks - padLen;
}

#endif