A test example of Android's RAS encryption algorithm

import java.security.Key;   
import java.security.KeyFactory;   
import java.security.KeyPair;   
import java.security.KeyPairGenerator;   
import java.security.PrivateKey;   
import java.security.PublicKey;   
import java.security.interfaces.RSAPrivateKey;   
import java.security.interfaces.RSAPublicKey;   
import java.security.spec.PKCS8EncodedKeySpec;   
import java.security.spec.X509EncodedKeySpec;   

import javax.crypto.Cipher;   

import sun.misc.BASE64Decoder;   
import sun.misc.BASE64Encoder;   

    
public class RSAHelper {   

        
      public static PublicKey getPublicKey(String key) throws Exception {   
            byte[] keyBytes;   
            keyBytes = (new BASE64Decoder()).decodeBuffer(key);   

            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);   
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");   
            PublicKey publicKey = keyFactory.generatePublic(keySpec);   
            return publicKey;   
      }   

      public static PrivateKey getPrivateKey(String key) throws Exception {   
            byte[] keyBytes;   
            keyBytes = (new BASE64Decoder()).decodeBuffer(key);   

            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);   
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");   
            PrivateKey privateKey = keyFactory.generatePrivate(keySpec);   
            return privateKey;   
      }   

        
      public static String getKeyString(Key key) throws Exception {   
            byte[] keyBytes = key.getEncoded();   
            String s = (new BASE64Encoder()).encode(keyBytes);   
            return s;   
      }   

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

            KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");   
            // The key figures    
            keyPairGen.initialize(1024);   
            // The key to    
            KeyPair keyPair = keyPairGen.generateKeyPair();   

            //  The public key    
            PublicKey publicKey = (RSAPublicKey) keyPair.getPublic();   

            //  The private key    
            PrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();   

            String publicKeyString = getKeyString(publicKey);   
            System.out.println("public:\n" + publicKeyString);   

            String privateKeyString = getKeyString(privateKey);   
            System.out.println("private:\n" + privateKeyString);   

            // Encryption class    
            Cipher cipher = Cipher.getInstance("RSA");//Cipher.getInstance("RSA/ECB/PKCS1Padding");   

            // clear    
            byte[] plainText = " We're all right! Email: @sina.com".getBytes();   

            // encryption    
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);   
            byte[] enBytes = cipher.doFinal(plainText);   

           // Get the key through the key string    
            publicKey = getPublicKey(publicKeyString);   
            privateKey = getPrivateKey(privateKeyString);   

            // decryption    
            cipher.init(Cipher.DECRYPT_MODE, privateKey);   
            byte[]deBytes = cipher.doFinal(enBytes);   

            publicKeyString = getKeyString(publicKey);   
            System.out.println("public:\n" +publicKeyString);   

            privateKeyString = getKeyString(privateKey);   
            System.out.println("private:\n" + privateKeyString);   

            String s = new String(deBytes);   
            System.out.println(s);   

    
      }   

}