I'm trying to duplicate a hashing function in C to be used on an existing database of hashes and salts. However once I reduced how PHP gets a sha256 hash and how c gets one, I can't get the same hashes.
I have looked though quite a few methods of getting the same hashes in C, but I can't quite figure out what's wrong the C code. The C code works, but the output is not the same.
Here is the base of my PHP code, it takes password and uses a single space as a salt, the rest of the code is just to visualize and see the output:
<?php
$salt = ' ';
$password = 'password';
$temp1 = hash_hmac('sha256', $salt, $password, true);
echo "======================
<br>";
echo "password [${password}]
<br>";
echo "salt [${salt}]
<br>";
echo "======================
<br>";
echo gettype($temp1) . "
<br>";
echo "each char as dechex(ord(x))
<br>";
for ($i = 0; $i < strlen($temp1); ++$i) {
$x = dechex(ord($temp1[$i]));
echo "[$x] ";
}
echo "-------------------------
<br>";
echo "base64_encode
<br>";
echo base64_encode($temp1)."
<br>"; ?>
and the output
======================
password [password]
salt [ ]
======================
string
each char as dechex(ord(x))
[52] [33] [c] [6b] [2f] [b6] [22] [cd] [bb] [73] [93] [c2] [5c] [be] [6c] [f4] [d3] [a6] [26] [cc] [ef] [aa] [9] [5e] [e0] [93] [33] [8] [83] [8d] [9] [63] -------------------------
base64_encode
UjMMay+2Is27c5PCXL5s9NOmJszvqgle4JMzCIONCWM=
The C I'm using, this is the simplest of examples I could find. I am only looking to get the same hash output. It does not have to use this method. I also included the base64 include function I'm using just in case:
#include <string.h>
#include <stdio.h>
#include <openssl/evp.h>
#include <openssl/sha.h>
#include <openssl/pem.h>
#include <openssl/hmac.h>
#define PBKDF2_DIGEST_LENGTH SHA256_DIGEST_LENGTH
#define PBKDF2_SALT_PREFIX ""
#define PBKDF2_SALT_PREFIX_LENGTH strlen(PBKDF2_SALT_PREFIX)
#define PBKDF2_PRF_ALGORITHM_OLD EVP_sha512()
#define PBKDF2_DIGEST_LENGTH_OLD SHA512_DIGEST_LENGTH
#define PBKDF2_SALT_LENGTH 32
#define PBKDF2_RESULT_LENGTH PBKDF2_SALT_PREFIX_LENGTH + (2 * PBKDF2_DIGEST_LENGTH) + PBKDF2_SALT_LENGTH + 2
#define PBKDF2_ROUNDS 1000
#define PBKDF2_PRF_ALGORITHM EVP_sha256()
char *base64encode (const void *b64_encode_this, int encode_this_many_bytes){
BIO *b64_bio, *mem_bio; //Declares two OpenSSL BIOs: a base64 filter and a memory BIO.
BUF_MEM *mem_bio_mem_ptr; //Pointer to a "memory BIO" structure holding our base64 data.
b64_bio = BIO_new(BIO_f_base64()); //Initialize our base64 filter BIO.
mem_bio = BIO_new(BIO_s_mem()); //Initialize our memory sink BIO.
BIO_push(b64_bio, mem_bio); //Link the BIOs by creating a filter-sink BIO chain.
BIO_set_flags(b64_bio, BIO_FLAGS_BASE64_NO_NL); //No newlines every 64 characters or less.
BIO_write(b64_bio, b64_encode_this, encode_this_many_bytes); //Records base64 encoded data.
BIO_flush(b64_bio); //Flush data. Necessary for b64 encoding, because of pad characters.
BIO_get_mem_ptr(mem_bio, &mem_bio_mem_ptr); //Store address of mem_bio's memory structure.
BIO_set_close(mem_bio, BIO_NOCLOSE); //Permit access to mem_ptr after BIOs are destroyed.
BIO_free_all(b64_bio); //Destroys all BIOs in chain, starting with b64 (i.e. the 1st one).
BUF_MEM_grow(mem_bio_mem_ptr, (*mem_bio_mem_ptr).length + 1); //Makes space for end null.
(*mem_bio_mem_ptr).data[(*mem_bio_mem_ptr).length] = '\0'; //Adds null-terminator to tail.
return (*mem_bio_mem_ptr).data; //Returns base-64 encoded data. (See: "buf_mem_st" struct).
}
int main(void)
{
static unsigned char hb[PBKDF2_DIGEST_LENGTH];
static unsigned char hashBlock[PBKDF2_DIGEST_LENGTH];
char *password = "password";
char *salt = " ";
int passes = 1;
PKCS5_PBKDF2_HMAC(password, strlen(password), salt, strlen(salt) , passes, PBKDF2_PRF_ALGORITHM, PBKDF2_DIGEST_LENGTH, hb);
unsigned int i = 0;
printf("printf hex
");
while(i<32)
{
printf("[%x] ", hb[i]);
++i;
}
printf("
");
printf("base-64 encode
");
printf("%s
", base64encode(hb, 32));
return 0;
}
The output that C produces, basically to visualize the output:
./pbkdf2_hack
printf hex
[f8] [8b] [fe] [58] [64] [f8] [a] [ef] [c0] [da] [b2] [97] [42] [ce] [b3] [83] [67] [85] [a5] [f2] [c8] [94] [7b] [2d] [82] [5d] [8a] [a5] [c0] [46] [9a] [24]
base-64 encode
+Iv+WGT4Cu/A2rKXQs6zg2eFpfLIlHstgl2KpcBGmiQ=
Compiling, in case something needs to be different here:
gcc pbkdf2_example.c -lcrypto -o pbkdf2_example
