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 <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26 
27 /**
28  * Simple program to generate a key based on PBKDF2 with preset inputs.
29  *
30  * Will print out the salt and key in hex.
31  */
32 
33 #define SALT_LEN 8
34 #define ROUNDS 1024
35 #define KEY_BITS 128
36 
main(int argc,char * argv[])37 int main(int argc, char* argv[])
38 {
39     if (argc != 2) {
40         fprintf(stderr, "Usage: %s <password>\n", argv[0]);
41         exit(1);
42     }
43 
44     int fd = open("/dev/urandom", O_RDONLY);
45     if (fd < 0) {
46         fprintf(stderr, "Could not open /dev/urandom: %s\n", strerror(errno));
47         close(fd);
48         exit(1);
49     }
50 
51     unsigned char salt[SALT_LEN];
52 
53     if (read(fd, &salt, SALT_LEN) != SALT_LEN) {
54         fprintf(stderr, "Could not read salt from /dev/urandom: %s\n", strerror(errno));
55         close(fd);
56         exit(1);
57     }
58     close(fd);
59 
60     unsigned char rawKey[KEY_BITS];
61 
62     if (PKCS5_PBKDF2_HMAC_SHA1(argv[1], strlen(argv[1]), salt, SALT_LEN,
63             ROUNDS, KEY_BITS, rawKey) != 1) {
64         fprintf(stderr, "Could not generate PBKDF2 output: %s\n", strerror(errno));
65         exit(1);
66     }
67 
68     printf("salt=");
69     for (int i = 0; i < SALT_LEN; i++) {
70         printf("%02x", salt[i]);
71     }
72     printf("\n");
73 
74     printf("key=");
75     for (int i = 0; i < (KEY_BITS / 8); i++) {
76         printf("%02x", rawKey[i]);
77     }
78     printf("\n");
79 }
80