dsaa

/**
 * Created by Amos on 01.05.2016.
 */
import java.security.*;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import javax.crypto.Cipher;

public class Task2 {
    public static void main(String[] args) throws Exception {
        String h64 ="5Krr6MTbKvO/SByx21n3hj1dZ2U9A+8AU/LbsKHHWX4=";
        String c64 ="wtPRW7biV8tTOC0rtWIbN5CpYcrDPD7LU2QoHOIXBnX4cYphWwBlnA1aVUHmGLSq8XSoOtbVLULyO4MjHjbjS3w4pysnQfXFH4BSx/rkQrMHIIVfMqtYU7/j/RZsVNLt3+6mAntMZjrc/uOrgrP18thu1p+2c81iWevphbN8fs1LM1aPuXFF5pSPHls3x+QRtT2xyQU4RMoI5W1jq06mEDOqyTB2VPEwrYsboRBBsW3yutHoW+FaOyeuzsJGSuRsSMU/u77SLLiDlNOU8QB2Pf7s7xLQO3pOsru50DoRTolH5DNNzVZGSF6yz9utgcDzIIfRLSUNqqxBs17/HMQKa2++MN3m4+L1/61D3bYBTTNwsSNzqtedomPM8HExuE9WaFTnRRC4Sp0sokCDOhsShG15gzfMH/ooKas8Nv4V7thM2zptL+Luxm9FQuPqpSXjy3HVDT4ZyQrSq+l+1+zMUhnMaZjtqam0SSIJJ2FxlO3eYj/+8eTYNqXoPmjwdEPkFxNUeZTEHCmUskh7T4p0oOBFlTT2mKkEQI2UlwOog8mOWwTXl4kO/w3PC6wiXtjO4qwCxwf6hE9tsDxW+1NQRfhcQL/Ok8m3ntj7dVgG/ov+2DSPvADE/3yfqReuU1GZuV+SKPVKQ/fB7nIRYIxcEFAuxx5XRE+XCxrAiNfrhSI=";

        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
        SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
        keyGen.initialize(4096, random);

        KeyPair pair = keyGen.generateKeyPair();
        PrivateKey priv = pair.getPrivate();
        PublicKey pub = pair.getPublic();

        //decode from b64
        byte[] c = Base64.getDecoder().decode(c64);
        byte[] h = Base64.getDecoder().decode(h64);

        //create signature
        Signature signature = Signature.getInstance("SHA256withRSA");
        signature.initSign(priv);
        signature.update(c);
        byte[] sig = signature.sign();

        //encode from b64
        String sig64 = Base64.getEncoder().encodeToString(sig);
        String pk64 = Base64.getEncoder().encodeToString(pub.getEncoded());

        System.out.println(sig64);
        System.out.println(pk64);
    }
}