package util;

import java.nio.charset.StandardCharsets;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.util.Base64;

public class RSASignature {
    public static byte[] sign(String plainText, PrivateKey privateKey) throws Exception {
        Signature signature = Signature.getInstance("SHA256withRSA");
        signature.initSign(privateKey);
        signature.update(plainText.getBytes());
        return signature.sign();
    }

    public static boolean verify(String message, String cipherText, PublicKey publicKey) throws Exception {
        byte[] signature =  Base64.getDecoder().decode(cipherText);
        Signature verifier = Signature.getInstance("SHA256withRSA");
        verifier.initVerify(publicKey);
        verifier.update(message.getBytes(StandardCharsets.UTF_8));
        return verifier.verify(signature);
    }
}