1 | /* Encrypting Passwords |
2 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
3 | |
4 | This program is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU General Public License |
6 | as published by the Free Software Foundation; either version 2 |
7 | of the License, or (at your option) any later version. |
8 | |
9 | This program is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
12 | GNU General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU General Public License |
15 | along with this program; if not, see <https://www.gnu.org/licenses/>. |
16 | */ |
17 | |
18 | #include <stdio.h> |
19 | #include <unistd.h> |
20 | #include <crypt.h> |
21 | |
22 | int |
23 | main(void) |
24 | { |
25 | unsigned char ubytes[16]; |
26 | char salt[20]; |
27 | const char *const saltchars = |
28 | "./0123456789ABCDEFGHIJKLMNOPQRST" |
29 | "UVWXYZabcdefghijklmnopqrstuvwxyz" ; |
30 | char *hash; |
31 | int i; |
32 | |
33 | /* Retrieve 16 unpredictable bytes from the operating system. */ |
34 | if (getentropy (buffer: ubytes, length: sizeof ubytes)) |
35 | { |
36 | perror ("getentropy" ); |
37 | return 1; |
38 | } |
39 | |
40 | /* Use them to fill in the salt string. */ |
41 | salt[0] = '$'; |
42 | salt[1] = '5'; /* SHA-256 */ |
43 | salt[2] = '$'; |
44 | for (i = 0; i < 16; i++) |
45 | salt[3+i] = saltchars[ubytes[i] & 0x3f]; |
46 | salt[3+i] = '\0'; |
47 | |
48 | /* Read in the user's passphrase and hash it. */ |
49 | hash = crypt (phrase: getpass (prompt: "Enter new passphrase: " ), salt: salt); |
50 | if (!hash || hash[0] == '*') |
51 | { |
52 | perror ("crypt" ); |
53 | return 1; |
54 | } |
55 | |
56 | /* Print the results. */ |
57 | puts (s: hash); |
58 | return 0; |
59 | } |
60 | |