Java Requires Chilkat v11.0.0+

Verify an RSA Signature Against the Signed Hash

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the hash that was signed. Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.PublicKey;
import com.chilkatsoft.chilkat2.Rsa;

public class ChilkatExample {

    public static void main(String[] args) {
        BinData bd = new BinData();
        for (int i = 0; i <= 100; i++) {
            bd.appendEncoded("000102030405060708090A0B0C0D0E0F", "hex");
        }

        String sha256_base64 = bd.getHash("sha256", "base64");
        System.out.println("sha256 hash in base64 format: " + sha256_base64);

        String base64_rsa_sig = "AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w==";

        // Get the public key to be used for signature verification.
        PublicKey pubKey = new PublicKey();
        try {
            pubKey.loadFromFile("rsaKeys/chilkat-rsa-2048.pem");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        Rsa rsa = new Rsa();
        try {
            rsa.usePublicKey(pubKey);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Verify the hash against the signature.
        rsa.setEncodingMode("base64");

        try {
            rsa.verifyHashENC(sha256_base64, "sha256", base64_rsa_sig);
            System.out.println("Signature valid.");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            System.out.println("Signature invalid.");
        }
    }
}