basersaexample.java

sip CMSEnvelopedData

package chapter4;

import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;

import javax.crypto.Cipher;

/**
 * Basic RSA example.
 */
public class BaseRSAExample
{
    public static void main(
        String[]    args)
        throws Exception
    {
        byte[]           input = new byte[] { (byte)0xbe, (byte)0xef };
        Cipher	         cipher = Cipher.getInstance("RSA/None/NoPadding", "BC");
        KeyFactory       keyFactory = KeyFactory.getInstance("RSA", "BC");
        
        // create the keys

        RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(
                new BigInteger("d46f473a2d746537de2056ae3092c451", 16),
                new BigInteger("11", 16));
        RSAPrivateKeySpec privKeySpec = new RSAPrivateKeySpec(
                new BigInteger("d46f473a2d746537de2056ae3092c451", 16),  
                new BigInteger("57791d5430d593164082036ad8b29fb1", 16));
        
        RSAPublicKey pubKey = (RSAPublicKey)keyFactory.generatePublic(pubKeySpec);
        RSAPrivateKey privKey = (RSAPrivateKey)keyFactory.generatePrivate(privKeySpec);

        System.out.println("input : " + Utils.toHex(input));

        // encryption step
        
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);

        byte[] cipherText = cipher.doFinal(input);

        System.out.println("cipher: " + Utils.toHex(cipherText));
        
        // decryption step

        cipher.init(Cipher.DECRYPT_MODE, privKey);

        byte[] plainText = cipher.doFinal(cipherText);
        
        System.out.println("plain : " + Utils.toHex(plainText));
    }
}