Question

Sometimes you have to implement C-Code and Encryption so I have a Problem with my C-Code implementation of hmac256 or sha2_hmac Implementation:

unsigned char key[19] = { "abcdef" };
size_t keylen = 18;
unsigned char input[64] = {"123456789"}; 
size_t ilen = 63;         
unsigned char output[32];
int is224 = 0;


sha2_hmac(key, keylen, input, ilen, output, is224);

char result[64] = {};
char result2[64] = {};

for(int j = 0; j < 32; j++) {
        sprintf(result, "%X", output[j]);
        strcat(result2, result);
}

But the result is too short, when I compare it to the C# Code.

Answer 1

You have to adjust your sprintf() function call like this:

sprintf(result, "%02X", output[j]);