Sign SHA512-HMAC with private key in java

Question

I want to build a function that sign a SHA512 HMAC with a Private key with a password to open that file. I have done that with Javascript but I'm not able to do it in JAVA. here is my code in Javascript:-

const fs = require('fs')
const crypto = require('crypto');

const getSignatureByInput = (input, crt) => {
    let privatePem = fs.readFileSync(crt);
    let key = privatePem.toString('ascii');
    let sign = crypto.createSign('RSA-SHA512');
    sign.write(input)
    let signature = sign.sign({ key, passphrase: 'Password' }, 'hex')
    return signature;
}

// Usage
let hamc = crypto.createHmac("sha512", '12345678-73a8-414c-9832-fcd4b2d9b362').update(
    JSON.stringify({
    "body": {
        "Id": "123"
    }
})
).digest("hex");


console.log(hamc)

let signatureSignedByPrivateKey = getSignatureByInput(hamc,'./private.key');
console.log(signatureSignedByPrivateKey)

and the below is the example of my private key:-

Appreciate your support. Thanks in advance...

Answer 1

I found a way to solve this thanks @pra-a for answering a question posted earlier Link here .

I will share my solution below.

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPrivateKey;
import java.security.*;
import java.security.spec.*;


public class Main {
    public static final String PRIVATE_KEY="./private.der";

    public static void main(String[] args) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
    // write your code here

        //get the private key
        File file = new File(PRIVATE_KEY);
        FileInputStream fis = new FileInputStream(file);
        DataInputStream dis = new DataInputStream(fis);

        byte[] keyBytes = new byte[(int) file.length()];
        dis.readFully(keyBytes);
        dis.close();

        PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        RSAPrivateKey privKey = (RSAPrivateKey) kf.generatePrivate(spec);

        Mac sha512Hmac;
        String result = "";
        final String key = "'12345678-73a8-414c-9832-fcd4b2d9b362'";
        String signature = "";
        String body = "{\n" +
                "    \"body\": {\n" +
                "        \"Id\": \"123\"\n" +
                "    }\n" +
                "}";
        try {
            final String HMAC_SHA512 = "HmacSHA512";
            final byte[] byteKey = key.getBytes(StandardCharsets.UTF_8);
            sha512Hmac = Mac.getInstance(HMAC_SHA512);
            SecretKeySpec keySpec = new SecretKeySpec(byteKey, HMAC_SHA512);
            sha512Hmac.init(keySpec);
            byte[] macData = sha512Hmac.doFinal(body.getBytes(StandardCharsets.UTF_8));

            // Can either base64 encode or put it right into hex
            //result = Base64.getEncoder().encodeToString(macData);
            result = bytesToHex(macData);
            
            signature = sign(result, privKey);


        } catch (NoSuchAlgorithmException | InvalidKeyException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // Put any cleanup here
            System.out.println("Done");
        }
    }

    private static final char[] HEX_ARRAY = "0123456789abcdef".toCharArray();
    public static String bytesToHex(byte[] bytes) {
        char[] hexChars = new char[bytes.length * 2];
        for (int j = 0; j < bytes.length; j++) {
            int v = bytes[j] & 0xFF;
            hexChars[j * 2] = HEX_ARRAY[v >>> 4];
            hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
        }
        return new String(hexChars);
    }


    public static PrivateKey readPrivateKeyII(String filename) throws Exception{
        InputStream in = new FileInputStream(filename);
        byte[] privateKeydata = new byte[in.available()];
        in.read(privateKeydata);
        in.close();
        KeyFactory privateKeyFactory = KeyFactory.getInstance("RSA");
        PKCS8EncodedKeySpec encodedKeySpec = new PKCS8EncodedKeySpec(privateKeydata);
        PrivateKey privateKey = privateKeyFactory.generatePrivate(encodedKeySpec);
        return  privateKey;
    }

    public static String sign(String plainText, PrivateKey privateKey) throws Exception {
        Signature privateSignature = Signature.getInstance("SHA512withRSA");
        privateSignature.initSign(privateKey);
        privateSignature.update(plainText.getBytes(StandardCharsets.UTF_8));

        byte[] signature = privateSignature.sign();

        return bytesToHex(signature);
    }
}

Sign SHA512-HMAC with private key in java

Question

1 answers

solution1
0 ACCPTED 2022-01-19 08:07:54

Sign SHA512-HMAC with private key in java

Question

1 answers

solution1 0 ACCPTED 2022-01-19 08:07:54

solution1
0 ACCPTED 2022-01-19 08:07:54