Encrypting SHA512 Example in c

Question

I can't find an example of encrypting a string with "SHA-512" in C. Can someone help me with some code or a link. Thank you in advance.

SHA 512 is not an encryption algorithm. Rather it's used for hashing. Where are you stuck? What are you really trying to do? — Mike Dinescu, Jul 03 '13 at 19:19
See [here](http://stackoverflow.com/questions/12772102/how-to-convert-openssl-sha-512-hash-to-gmp-number-to-use-in-rsa-encryption-metho) on SO. — kgdesouz, Jul 03 '13 at 19:20

score 15 · Answer 1 · edited Jul 22 '15 at 12:02

15

SHA-512 is not an encryption algorithm, it is a cryptographic hash, which is completely different.

One library you can use to perform SHA hashes is OpenSSL. Here's an example of computing the raw SHA-512 hash of some data with OpenSSL:

#include <openssl/sha.h>
...
char data[] = "data to hash";
char hash[SHA512_DIGEST_LENGTH];
SHA512(data, sizeof(data) - 1, hash);

// 'hash' now contains the raw 64-byte binary hash.  If you want to print it out
// in a human-readable format, you'll need to convert it to hex, e.g.

edited Jul 22 '15 at 12:02

Iharob Al Asimi

52,653
6
59
97

answered Jul 03 '13 at 19:55

Adam Rosenfield

390,455
97
512
589

1

Helpful answer! However, I think you need to do sizeof(data)-1 to exclude the terminating null character. – JustinB Feb 16 '14 at 20:53
2

@JustinB yeah or he could use `strlen(data)` – jackcogdill Apr 15 '14 at 13:40
And thanks, I needed to see this answer. – jackcogdill Apr 15 '14 at 13:47

lathspell · Answer 2 · 2020-10-19T13:47:50.583

7

If you want to store passwords using SHA-512, please consider using a "salt" value to make rainbow-table attacks harder. Example, "12345678" would be a random string. "$6$" marks SHA-512:

#include <crypt.h>
#include <stdio.h>

int main() {
    char *hash = crypt("secret", "$6$12345678$");
    printf("hashed=%s\n", hash);
}

edited Oct 19 '20 at 13:47

answered Jul 05 '13 at 08:19

lathspell

3,040
1
30
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Thank u for the answer, i've found an SHA1 code, ans i used it, it's better than MD5 and still strong too. i will use salts values with the passwords and store the hashes in a file, only the super user can access that file. If i'm wrong correct me . – badr assa Jul 07 '13 at 00:51
`char *hash = crypt("secret", "$6$12345678");` This seems to be missing a '$' at the end of the salt. Format: `$6$$`. That is also what I've seen in many other examples. – GoinOff Oct 19 '20 at 13:31
Thanks for pointing out, I edited the example. Both produce the same result in Linux, though. – lathspell Oct 19 '20 at 13:49

yeyo · Answer 3 · 2014-12-11T00:55:29.853

You can use GLib for this matter, be aware of G_CHECKSUM_SHA512, it might require you to install a newer version of GLib, visit: https://developer.gnome.org/glib/stable/glib-Data-Checksums.html

#include <glib.h>
#include <string.h>

int
main(void)
{
        char   *string  = "Hello World";
        gchar  *sha512;

        sha512 = g_compute_checksum_for_string(G_CHECKSUM_SHA512, string, strlen(string));
        g_print("%s\n", sha512);
        g_free(sha512);
        return 0; 
}

compile

$ gcc -o sha512 sha512.c `pkg-config --cflags --libs glib-2.0`

Encrypting SHA512 Example in c

3 Answers3