MainClass.java

package project.rsa.test;

import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import java.security.*;
import java.security.spec.EncodedKeySpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;

/**
 * Created by Suro Smith on 2/22/2017
 */
public class MainClass {

    static String privateKeyString = "MIICXAIBAAKBgQC4CLV9wxuJ14kXs1BDowrTLtF/OqmOnpllywVy/A/Ie5eUF2mr" +
            "rEGRNadGDqocTmcsd6ZQFMtXyvFHirpTMGJwougm/E/46v9PIXkloGxrM4HItm9x" +
            "pON7ydMK2GU4B10M0hi6/3QNDXDGFQk2YXAtXjjkmgxHo8DCcM751nmEpQIDAQAB" +
            "AoGAGqPwGd93ihGwX8TuVowwkfeSDhfg2atty0WDaWzBoCT8AU0OV/KcnzekGkkf" +
            "KO/UkaRUZ/1Knk/bc57KcCZt6V9F6XL0mA2RF0PMtf8NPHFof/mLd32ydLLagLS4" +
            "rstEYNMuPB4YU4c3WbKH7xvnsT5+h9O2hFP3tqNXOKp0pYECQQDmzMoOtMbqfmOD" +
            "8urKgrmxwfJXatbG7Oamd+uKjigtaOJGWgCiOB2NF7wkKAmyQ6lUvHRfEZ58O+Az" +
            "HFZrqN2FAkEAzCC9iRas22xc5fpSX0+Eza9JIlhqzbhYmp7/6k+/rrF8Sw/jgZ+7" +
            "z9HgeCKDY5+LuPiVn8GWfsIYQxk0mfmkoQJBAJU3g89cO1qyGh7d98S0HeB6FvdD" +
            "oNZ9pWWtFIDBBeLN87UuTUiT5S8qUD5EEHjLW/fn24j3eDKz93Cz+n+ibo0CQFAb" +
            "XSZKbsWhjgd2qBLdSvnJG0NOPYPEH4l2cmoKp+evoV53usmo3PSeoZ+js7pJ53RM" +
            "obNTLnNKSmkyoBD5BmECQCUEToRcCcNsiBER/r7AcYmD+kIkImrQ8ULz4Hx7Y9DB" +
            "JDJoqi5gcUAoqYCl3xf348TCOQ44/pU60654DfJxR4Q=";

    static String publicKeyString = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC4CLV9wxuJ14kXs1BDowrTLtF/" +
            "OqmOnpllywVy/A/Ie5eUF2mrrEGRNadGDqocTmcsd6ZQFMtXyvFHirpTMGJwougm" +
            "/E/46v9PIXkloGxrM4HItm9xpON7ydMK2GU4B10M0hi6/3QNDXDGFQk2YXAtXjjk" +
            "mgxHo8DCcM751nmEpQIDAQAB";

    private static PrivateKey privateKey;
    private static PublicKey publicKey;

    public static void main(String[] args) throws Exception {

        byte[] encodedPrivateKey = Base64.getDecoder().decode(privateKeyString);
        byte[] encodedPublicKey = Base64.getDecoder().decode(publicKeyString);
        try {
            EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encodedPrivateKey);
            PKCS8EncodedKeySpec publicKeySpec = new PKCS8EncodedKeySpec(encodedPublicKey);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            privateKey = keyFactory.generatePrivate(keySpec);
            publicKey = keyFactory.generatePublic(publicKeySpec);
        } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
            e.printStackTrace();
        }
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(1, publicKey);
        String encrypted = new String(cipher.doFinal("DUA LIPA".getBytes()));
        System.out.println(encrypted);
    }

}