OpenSSL SHA1 demo

README.md

In response to this question:

This works correctly for me on Ubuntu, and produces the same output each time I run it.

Compile with:

gcc c.c -lssl -lcrypto -o c

Run with:

./c

Output:

c9 16 e7 1d 73 3d 06 cb 77 a4 77 5d e5 f7 7f d0 b4 80 a7 e8 

c.c

#include <stdio.h>
#include <string.h>
#include <openssl/sha.h>

int main(void)
{
    int i;

    unsigned char buffer[] = "Whatever"; //input, which is always the same one
    unsigned char obuf[20];

    SHA1(buffer, strlen(buffer), obuf);

    for (i = 0; i < 20; i++) {
        printf("%02x ", obuf[i]);
    }
    printf("\n");

    return 0;
}