Files
GmSSL/crypto/ffx/ffx.c
2016-04-10 00:01:46 +02:00

348 lines
9.0 KiB
C

/* ====================================================================
* Copyright (c) 2015 The GmSSL 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 GmSSL Project.
* (http://gmssl.org/)"
*
* 4. The name "GmSSL Project" must not be used to endorse or promote
* products derived from this software without prior written
* permission. For written permission, please contact
* guanzhi1980@gmail.com.
*
* 5. Products derived from this software may not be called "GmSSL"
* nor may "GmSSL" appear in their names without prior written
* permission of the GmSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the GmSSL Project
* (http://gmssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE GmSSL 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 GmSSL 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.
* ====================================================================
*
*/
/*
* Format-Preserve Encryption
* implementation of NIST 800-38G FF1 schemes
*
* FPE is used to encrypt strings such as credit card numbers and phone numbers
* the ciphertext is still in valid format, for example:
* FPE_encrypt("13810631266") == "98723498792"
* the output is still 11 digits
*/
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#include <inttypes.h>
#include <openssl/err.h>
#include <openssl/aes.h>
#include "ffx.h"
#define FFX_MIN_DIGITS 6
#define FFX_MAX_DIGITS 18
#define FFX_MIN_TWEAKLEN 4
#define FFX_MAX_TWEAKLEN 11
#define FFX_NUM_ROUNDS 10
static uint32_t modulo[] = {
1,
10,
100,
1000,
10000,
100000,
1000000,
10000000,
100000000,
1000000000,
1000000000,
};
int FFX_init(FFX_CTX *ctx, int flag, const unsigned char *key, int keybits)
{
ctx->flag = flag;
if (AES_set_encrypt_key(key, keybits, &ctx->key) < 0) {
fprintf(stderr, "error: %s: %s: %d\n", __FUNCTION__, __FILE__, __LINE__);
return -1;
}
return 0;
}
void FFX_cleanup(FFX_CTX *ctx)
{
memset(ctx, 0, sizeof(*ctx));
}
int FFX_encrypt(FFX_CTX *ctx, const char *in, size_t inlen,
const unsigned char *tweak, size_t tweaklen, char *out)
{
int llen, rlen;
uint32_t lval, rval;
unsigned char pblock[16] = {
0x01, 0x02, 0x01, 0x0a, 0x00, 0x00, 0x0a, 0xff,
0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00};
unsigned char qblock[16];
char lbuf[FFX_MAX_DIGITS/2 + 2];
uint64_t yval;
int i;
assert(out);
assert(in);
assert(tweak);
if (inlen > strlen(in) ||
inlen < FFX_MIN_DIGITS || inlen > FFX_MAX_DIGITS) {
fprintf(stderr, "%s: invalid digits length\n", __FUNCTION__);
return -1;
}
for (i = 0; i < inlen; i++) {
if (!isdigit(in[i])) {
fprintf(stderr, "%s: invalid digits format\n", __FUNCTION__);
return -1;
}
}
llen = inlen / 2;
rlen = inlen - llen;
if (tweaklen < FFX_MIN_TWEAKLEN || tweaklen > FFX_MAX_TWEAKLEN) {
fprintf(stderr, "%s: invalid tweak length\n", __FUNCTION__);
return -1;
}
memcpy(lbuf, in, llen);
lbuf[llen] = 0;
lval = atoi(lbuf);
rval = atoi(in + llen);
pblock[7] = llen & 0xff;
pblock[8] = inlen & 0xff;
pblock[12] = tweaklen & 0xff;
AES_encrypt(pblock, pblock, &ctx->key);
memset(qblock, 0, sizeof(qblock));
memcpy(qblock, tweak, tweaklen);
for (i = 0; i < FFX_NUM_ROUNDS; i += 2) {
unsigned char rblock[16];
int j;
qblock[11] = i & 0xff;
memcpy(qblock + 12, &rval, sizeof(rval));
for (j = 0; j < sizeof(rblock); j++) {
rblock[j] = pblock[j] ^ qblock[j];
}
AES_encrypt(rblock, rblock, &ctx->key);
yval = *((uint64_t *)rblock) % modulo[llen];
lval = (lval + yval) % modulo[llen];
qblock[11] = (i + 1) & 0xff;
memcpy(qblock + 12, &lval, sizeof(lval));
for (j = 0; j < sizeof(rblock); j++) {
rblock[j] = pblock[j] ^ qblock[j];
}
AES_encrypt(rblock, rblock, &ctx->key);
yval = *((uint64_t *)rblock) % modulo[rlen];
rval = (rval + yval) % modulo[rlen];
}
memset(out, '0', inlen);
sprintf(lbuf, "%d", rval);
memcpy(out + rlen - strlen(lbuf), lbuf, strlen(lbuf));
sprintf(lbuf, "%d", lval);
strcpy(out + inlen - strlen(lbuf), lbuf);
return 0;
}
int FFX_decrypt(FFX_CTX *ctx, const char *in, size_t inlen,
const unsigned char *tweak, size_t tweaklen, char *out)
{
int llen, rlen;
uint32_t lval, rval;
unsigned char pblock[16] = {
0x01, 0x02, 0x01, 0x0a, 0x00, 0x00, 0x0a, 0xff,
0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00};
unsigned char qblock[16];
char lbuf[FFX_MAX_DIGITS/2 + 2];
uint64_t yval;
int i;
assert(out);
assert(in);
assert(tweak);
if (inlen > strlen(in) ||
inlen < FFX_MIN_DIGITS || inlen > FFX_MAX_DIGITS) {
fprintf(stderr, "%s: invalid digits length\n", __FUNCTION__);
return -1;
}
for (i = 0; i < inlen; i++) {
if (!isdigit(in[i])) {
fprintf(stderr, "%s: invalid digits format\n", __FUNCTION__);
return -1;
}
}
rlen = inlen / 2;
llen = inlen - rlen;
if (tweaklen < FFX_MIN_TWEAKLEN || tweaklen > FFX_MAX_TWEAKLEN) {
fprintf(stderr, "%s: invalid tweak length\n", __FUNCTION__);
return -1;
}
memcpy(lbuf, in, llen);
lbuf[llen] = 0;
lval = atoi(lbuf);
rval = atoi(in + llen);
pblock[7] = rlen & 0xff;
pblock[8] = inlen & 0xff;
pblock[12] = tweaklen & 0xff;
AES_encrypt(pblock, pblock, &ctx->key);
memset(qblock, 0, sizeof(qblock));
memcpy(qblock, tweak, tweaklen);
for (i = FFX_NUM_ROUNDS - 1; i > 0; i -= 2) {
unsigned char rblock[16];
int j;
qblock[11] = i & 0xff;
memcpy(qblock + 12, &rval, sizeof(rval));
for (j = 0; j < sizeof(rblock); j++) {
rblock[j] = pblock[j] ^ qblock[j];
}
AES_encrypt(rblock, rblock, &ctx->key);
yval = *((uint64_t *)rblock) % modulo[llen];
lval = (lval >= yval) ? (lval - yval) : lval + modulo[llen] - yval;
qblock[11] = (i - 1) & 0xff;
memcpy(qblock + 12, &lval, sizeof(lval));
for (j = 0; j < sizeof(rblock); j++) {
rblock[j] = pblock[j] ^ qblock[j];
}
AES_encrypt(rblock, rblock, &ctx->key);
yval = *((uint64_t *)rblock) % modulo[rlen];
rval = (rval >= yval) ? (rval - yval) : rval + modulo[rlen] - yval;
}
memset(out, '0', inlen);
sprintf(lbuf, "%d", rval);
memcpy(out + rlen - strlen(lbuf), lbuf, strlen(lbuf));
sprintf(lbuf, "%d", lval);
strcpy(out + inlen - strlen(lbuf), lbuf);
return 0;
}
static int test()
{
char buf[100];
char buf2[100];
unsigned char key[32] = {0};
unsigned char tweak[8] = { 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38 };
FFX_CTX ctx;
int r;
ERR_load_crypto_strings();
if (FFX_init(&ctx, 0, key, sizeof(key) * 8) < 0) {
ERR_print_errors_fp(stderr);
fprintf(stderr, "%s: %d\n", __FILE__, __LINE__);
return -1;
}
char *in = "99999999999999999";
r = FFX_encrypt(&ctx, in, strlen(in), tweak, sizeof(tweak), buf);
if (r < 0) {
printf("failed\n");
return -1;
}
printf("%s\n", buf);
printf("\n");
r = FFX_decrypt(&ctx, buf, strlen(buf), tweak, sizeof(tweak), buf2);
printf("%s\n", buf2);
return 0;
}
static int luhn_table[10] = {0, 2, 4, 6, 8, 1, 3, 5, 7, 9};
/*
* 7992739871, checksum = 3
*/
int FFX_compute_luhn(const char *in, size_t inlen)
{
int r = 0;
int i;
for (i = inlen - 1; i >= 0; i--) {
int a;
if (!isdigit(in[i])) {
fprintf(stderr, "%s: invalid digit string\n", __FUNCTION__);
return -2;
}
a = in[i] - '0';
if (i % 2 != inlen % 2)
a = luhn_table[a];
r += a;
}
r = ((r * 9) % 10) + '0';
return r;
}
#if 0
int luhn_test()
{
char *digits = "7992739871";
int r = compute_luhn(digits, strlen(digits));
printf("%c", r);
return 0;
}
#endif