HMAC SHA256 sign on Java, Verify on C++ private-public keys - c++

Question

I try to sign some data by Java with private key and then verify it by C++ with public key. I user Java as client and C++ as server.
Java run on Windows, C++ on Ubuntu
in Java I use
key = "MIIEowIBAAKCAQ......s8mFoA2"; //private key
byte[] b1 = Base64.decodeBase64(key);
this.Sign = hmacSha256Base64("test", b1);
/**************/
public static String hmacSha256Base64(String message, byte[] secretKey) throws
NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException, NoSuchProviderException {
Mac hmacSha256;
try {
hmacSha256 = Mac.getInstance("HmacSHA256", "BC");
} catch (NoSuchAlgorithmException nsae) {
hmacSha256 = Mac.getInstance("HMAC-SHA-256");
}
SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey, "HmacSHA256");
hmacSha256.init(secretKeySpec);
// Build and return signature
return Base64.encodeBase64String(hmacSha256.doFinal(message.getBytes("UTF-8")));
}
and on C++, to verify I real try different code, for example:
int verify_it(const unsigned char *msg, size_t mlen, const unsigned char *val, size_t vlen, EVP_PKEY *pkey)
{
/* Returned to caller */
int result = 0;
EVP_MD_CTX* ctx = NULL;
unsigned char buff[EVP_MAX_MD_SIZE];
size_t size;
int rc;
if (!msg || !mlen || !val || !vlen || !pkey)
return 0;
ctx = EVP_MD_CTX_new();
if (ctx == NULL) {
printf("EVP_MD_CTX_create failed, error 0x%lx\n", ERR_get_error());
goto err;
}
rc = EVP_DigestSignInit(ctx, NULL, EVP_sha256(), NULL, pkey);
if (rc != 1) {
printf("EVP_DigestSignInit failed, error 0x%lx\n", ERR_get_error());
goto err;
}
rc = EVP_DigestSignUpdate(ctx, msg, mlen);
if (rc != 1) {
printf("EVP_DigestSignUpdate failed, error 0x%lx\n", ERR_get_error());
goto err;
}
size = sizeof(buff);
rc = EVP_DigestSignFinal(ctx, buff, &size);
if (rc != 1) {
printf("EVP_DigestSignFinal failed, error 0x%lx\n", ERR_get_error());
goto err;
}
result = (vlen == size) && (CRYPTO_memcmp(val, buff, size) == 0);
err:
EVP_MD_CTX_free(ctx);
return result;
}
RSA* createPublicRSA(std::string TermId, bool is_local) {
RSA *rsa = NULL;
BIO *keybio;
FILE * fp = fopen((SettingsConfig["UserKeys"] + "user_public/" + TermId).c_str(), "rb");
if (fp != 0)
{
rsa = PEM_read_RSA_PUBKEY(fp, &rsa, NULL, NULL);
fclose(fp);
}
return rsa;
}
size_t calcDecodeLength(const char* b64input) {
size_t len = strlen(b64input), padding = 0;
if (b64input[len - 1] == '=' && b64input[len - 2] == '=') //last two chars are =
padding = 2;
else if (b64input[len - 1] == '=') //last char is =
padding = 1;
return (len * 3) / 4 - padding;
}
void Base64Decode(const char* b64message, unsigned char** buffer, size_t* length) {
BIO *bio, *b64;
int decodeLen = calcDecodeLength(b64message);
*buffer = (unsigned char*)malloc(decodeLen + 1);
(*buffer)[decodeLen] = '\0';
bio = BIO_new_mem_buf(b64message, -1);
b64 = BIO_new(BIO_f_base64());
bio = BIO_push(b64, bio);
*length = BIO_read(bio, *buffer, strlen(b64message));
BIO_free_all(bio);
}
std::string test = "XChhsTE....NkE="; //Sign from Java
std::string msg = "test";
RSA* publicRSA = createPublicRSA("#1.pem", false); //public key
EVP_PKEY* pubKey = EVP_PKEY_new();
EVP_PKEY_assign_RSA(pubKey, publicRSA);
unsigned char* encMessage;
size_t encMessageLength;
Base64Decode(test.c_str(), &encMessage, &encMessageLength);
int result_sign = verify_it((unsigned char*)msg.c_str(), msg.length(), encMessage, encMessageLength, pubKey);
std::cout << std::to_string(result_sign) << std::endl; //return 0
And any others examples return false. I don't know what is problem, please help! Thanks!
p.s. private key:
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
public key:
-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAra2jau89VIfcunyOth5O
08EZqFVSgVzk9Tv0ELG+zH89D/s0DMLSkACXUSYq2EFRXUS05doajB55ZVoD2qYi
UjJPrZDnPS+H3f/9tqRf+o2bbb4DWRd9MJbMt2E2Q8auIN3M49XvlQnZ2+dSvplL
epYv6H+fbILBsYfQUxh4RX5B+qvk1JdbMh1rhgLV6y9/lYkF3UlL8W5EBA2A1YQv
grwl/nBjXTTk3PVv+OmWGFRFE0BGuf7oYEuoX86732gAtLkImqLNeNNhgUVVhFiD
UOOyWjybxH9UiH28eYBZqzJlyY9D3xeC3ZUkTvfJOURK5t8vagS/t8Vu3xsMHWQ7
DwIDAQAB
-----END PUBLIC KEY-----
message: 12105333071
signaturee from Java: XChhsTE+Yr4wkiibvTFiLTMhJ8tLqYo7WQs///VtNkE=

Answer 1

Just using HMACSHA256 is not the same as Private/Public Key signature. The full name of HMACSHA256 is "Hash-based Message Authentication Code" and you "sign" and "verify" this with the same "key" that is just a byte array and has nothing to do with Private or Public Key.
Of course you can take the encoded bytes of the Private/Public key as input, but when doing so (I do NOT recommend this)
you need to pass the same key to the verification part.
I setup two small programs to show how it works. For Java I'm using your code except of using Bouncy Castle as "native" Java
should have this build in. As well I left out the apache-Base64-conversion as it's build in as well. The C#-part is the same program but has a "verification" output.
Both code samples do not have any exceptional handling and are for educational purposes only.
Result of Java-code:
HMAC SHA256 sign on Java, Verify on C++ private-public keys
hmacSha256 (Base64): /1qkanJi8onWOxVe02MO/Wf1922aKzSTSfJk6E7o1x0=
Result of C#-code:
HMAC SHA256 sign on Java, Verify on C++ private-public keys
HMACSHA256 in C#: /1qkanJi8onWOxVe02MO/Wf1922aKzSTSfJk6E7o1x0=
HMACSHA256 Java : /1qkanJi8onWOxVe02MO/Wf1922aKzSTSfJk6E7o1x0=
Hashes are equal: True
Java-code:
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
public class Org {
public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException {
System.out.println("HMAC SHA256 sign on Java, Verify on C++ private-public keys");
String message = "12105333071";
String key = "12345678901234567";
String result = hmacSha256Base64(message, key.getBytes(StandardCharsets.UTF_8));
System.out.println("hmacSha256 (Base64): " + result);
}
public static String hmacSha256Base64(String message, byte[] secretKey) throws
NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException {
Mac hmacSha256;
try {
hmacSha256 = Mac.getInstance("HmacSHA256");
} catch (NoSuchAlgorithmException nsae) {
hmacSha256 = Mac.getInstance("HMAC-SHA-256");
}
SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey, "HmacSHA256");
hmacSha256.init(secretKeySpec);
// Build and return signature
return Base64.getEncoder().encodeToString(hmacSha256.doFinal(message.getBytes("UTF-8")));
}
}
C#-code:
using System;
using System.Text;
using System.Security.Cryptography;
class Program
{
static void Main(string[] args)
{
Console.WriteLine("HMAC SHA256 sign on Java, Verify on C++ private-public keys");
string message = "12105333071";
string key = "12345678901234567";
string expectedHashBase64 = "/1qkanJi8onWOxVe02MO/Wf1922aKzSTSfJk6E7o1x0="; // from Java
// generate HMACSHA256
string hmacSha256DigestBase64 = HmacSha256DigestBase64(key, message);
Console.WriteLine("HMACSHA256 in C#: " + hmacSha256DigestBase64);
Console.WriteLine("HMACSHA256 Java : " + expectedHashBase64);
Console.WriteLine("Hashes are equal: " + hmacSha256DigestBase64.Equals(expectedHashBase64, StringComparison.OrdinalIgnoreCase));
//Console.ReadLine();
}
private static string HmacSha256DigestBase64(string secret, string message)
{
ASCIIEncoding encoding = new ASCIIEncoding();
byte[] keyBytes = encoding.GetBytes(secret);
byte[] messageBytes = encoding.GetBytes(message);
System.Security.Cryptography.HMACSHA256 cryptographer = new System.Security.Cryptography.HMACSHA256(keyBytes);
byte[] bytes = cryptographer.ComputeHash(messageBytes);
return Convert.ToBase64String(bytes);
}
}

Answer 2

Golang code to complete the collection (tested to produce the exactly same result as the java code form Michael Fehr:
package main
import (
"crypto/hmac"
"crypto/sha256"
"fmt"
b64 "encoding/base64"
)
func main() {
secret := "12345678901234567"
data := "12105333071"
fmt.Printf("Secret: %s Data: %s\n", secret, data)
// Create a new HMAC by defining the hash type and the key (as byte array)
h := hmac.New(sha256.New, []byte(secret))
// Write Data to it
h.Write([]byte(data))
// Get result and base64 encode the string
sha := b64.StdEncoding.EncodeToString(h.Sum(nil))
fmt.Println("Result: " + sha)
}