1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <openssl/evp.h>
18
19#include <sys/types.h>
20#include <errno.h>
21#include <fcntl.h>
22#include <stdio.h>
23#include <string.h>
24#include <unistd.h>
25
26/**
27 * Simple program to generate a key based on PBKDF2 with preset inputs.
28 *
29 * Will print out the salt and key in hex.
30 */
31
32#define SALT_LEN 8
33#define ROUNDS 1024
34#define KEY_BITS 128
35
36int main(int argc, char* argv[])
37{
38    if (argc != 2) {
39        fprintf(stderr, "Usage: %s <password>\n", argv[0]);
40        exit(1);
41    }
42
43    int fd = open("/dev/urandom", O_RDONLY);
44    if (fd < 0) {
45        fprintf(stderr, "Could not open /dev/urandom: %s\n", strerror(errno));
46        close(fd);
47        exit(1);
48    }
49
50    unsigned char salt[SALT_LEN];
51
52    if (read(fd, &salt, SALT_LEN) != SALT_LEN) {
53        fprintf(stderr, "Could not read salt from /dev/urandom: %s\n", strerror(errno));
54        close(fd);
55        exit(1);
56    }
57    close(fd);
58
59    unsigned char rawKey[KEY_BITS];
60
61    if (PKCS5_PBKDF2_HMAC_SHA1(argv[1], strlen(argv[1]), salt, SALT_LEN,
62            ROUNDS, KEY_BITS, rawKey) != 1) {
63        fprintf(stderr, "Could not generate PBKDF2 output: %s\n", strerror(errno));
64        exit(1);
65    }
66
67    printf("salt=");
68    for (int i = 0; i < SALT_LEN; i++) {
69        printf("%02x", salt[i]);
70    }
71    printf("\n");
72
73    printf("key=");
74    for (int i = 0; i < (KEY_BITS / 8); i++) {
75        printf("%02x", rawKey[i]);
76    }
77    printf("\n");
78}
79