Reimplementation of an old c++ project that uses SHA2 in nodejs? - c++

Question

I've to convert an old c++ project in nodejs. That project relies in sha2 (polarssl) to do some cryptography. I tried to do this using crypto but I failed since the outputs are completely different.
//here i declare 2 keys
unsigned char key1[] = {0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F};
unsigned char key2[] = {0xCC,0xCC,0xCC,0xCC,0xCC,0xCC,0xCC,0xCC,0xCC};
sha2_context sha_ctx;
// Part 1: Compute the key with key1 and key 2
sha2_starts( &sha_ctx, 0 );
sha2_update( &sha_ctx, key1, sizeof(key1) );
sha2_update( &sha_ctx, key2, sizeof(key2) );
sha2_finish( &sha_ctx, digest );
// Part 2: The HMAC SHA-2 HMAC start
sha2_hmac_starts( &sha_ctx, digest, 32, 0 );
// SHA-2 Update
sha2_hmac_update( &sha_ctx, buffer, 16 );
// SHA-2 Finish
sha2_hmac_finish( &sha_ctx, digest );
Here's my attempts:
Using crypto HMAC (I tried it even if I thought it was not the correct way)
var {key1, key2, key_expected, key_expected_hex} = common;
// They use http://asf.atmel.com/docs/latest/uc3c/html/sha2_8h.html
function test(){
var hmac = crypto.createHmac('SHA256', new Buffer([0x00]))
hmac.update(key1);
hmac.update(key2);
var r = hmac.digest('hex');
console.log({
output: r,
expected: key_expected_hex
})
return r === key_expected_hex;
}
Using npm 'sha2' library
const {SHA256} = require("sha2");
function test(){
var hmac = SHA256(key1);
hmac = SHA256(key2);
console.log(hmac);
var r = hmac.toString('hex');;
console.log({
output: r,
expected: key_expected_hex
})
return r === key_expected_hex;
}
Can someone help me out pointing me in the right direction?

Answer 1

In node.js the Part 1 consisting of computing the key for the hmac used in Part 2, should not use hmac but only sha256 as in the C++ code :
const crypto = require('crypto');
const key1 = new Buffer([0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F]);
const key2 = new Buffer([0xCC,0xCC,0xCC,0xCC,0xCC,0xCC,0xCC,0xCC,0xCC]);
// Part 1: Compute the key from key1 and key2
var h = crypto.createHash('sha256');
h.update(key1);
h.update(key2);
var keyForHmac = h.digest();
console.log('key: ' + keyForHmac.toString('hex'));
// Part 2: The HMAC SHA-256
var buffer = new Buffer([/* data to be HMACed */]);
var hmac = crypto.createHmac('sha256', keyForHmac);
hmac.update(buffer);
var hmacDigest = hmac.digest();
console.log('hmac: ' + hmacDigest.toString('hex'));