RSA

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 org.apache.commons.codec.binary.Base64;

/**
 *
 * @author jay
 * @time Dec 29, 20152:45:57 PM
 *
 */
public class RSA {

    private static String str = "中国";

    public static void main(String[] args) {
        jdkRSA();
    }

    public static void jdkRSA() {

        try {

            // 1.初始化秘钥
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
            keyPairGenerator.initialize(512);
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
            RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();

            System.out.println("public key : " + Base64.encodeBase64String(rsaPublicKey.getEncoded()));
            System.out.println("private key : " + Base64.encodeBase64String(rsaPrivateKey.getEncoded()));

            // 2.加密
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            byte[] result = cipher.doFinal(str.getBytes());
            System.out.println("加密后的内容 ： " + Base64.encodeBase64String(result));

            // 3.解密
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
            keyFactory = KeyFactory.getInstance("RSA");
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
            result = cipher.doFinal(result);
            System.out.println(new String(result));

            // 4.加密
            x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
            keyFactory = KeyFactory.getInstance("RSA");
            publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            result = cipher.doFinal(str.getBytes());
            System.out.println("加密后的内容 ： " + Base64.encodeBase64String(result));

            // 5.解密
            pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
            keyFactory = KeyFactory.getInstance("RSA");
            privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            result = cipher.doFinal(result);
            System.out.println(new String(result));

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

EncryptRSAUtil

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
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 java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;

/**
 *
 * @author jay
 * @time Dec 29, 20152:45:57 PM
 *
 */
public class EncryptRSAUtil {

    /**
     * 生成密钥对
     * @return
     */
    public static Map<String, String> generateKeyPair(){
        Map<String, String> map = new HashMap<String, String>();

        try {
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
            keyPairGenerator.initialize(512);
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
            RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();

            String publicKey = Base64.encodeBase64String(rsaPublicKey.getEncoded());
            String privateKey = Base64.encodeBase64String(rsaPrivateKey.getEncoded());

//            System.out.println( "public key : " + publicKey );
//            System.out.println( "private key : " + privateKey );

            map.put("publicKey", publicKey );
            map.put("privateKey", privateKey );
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return map;
    }

    /**
     * 通过公钥加密
     * @param str
     * @param publicKey
     * @return
     */
    public static String encrypt(String str,String rsaPublicKey){
        String returnStr = "";

        try {
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec( Base64.decodeBase64(rsaPublicKey) );
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            byte[] result = cipher.doFinal(str.getBytes());
            returnStr = Base64.encodeBase64String(result);
        } catch (Exception e) {
            e.printStackTrace();
        } 

        return returnStr;
    }

    /**
     * 通过密钥解密
     * @param str
     * @param publicKey
     * @return
     */
    public static String decrypt(String str,String rsaPrivateKey){
        String returnStr = "";

        try {
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec( Base64.decodeBase64(rsaPrivateKey) );
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            byte[] result = cipher.doFinal( Base64.decodeBase64(str) );
            returnStr = new String(result);
        } catch (Exception e) {
            e.printStackTrace();
        } 

        return returnStr;
    }

    public static void main(String[] args) {
         Map<String, String> map = generateKeyPair();

         String publicKey =  map.get("publicKey");
         String privateKey = map.get("privateKey");

         System.out.println( "Public Key : " + publicKey );
         System.out.println( "Private Key : " + privateKey );


         String str = "hello world";

         String encryptStr = encrypt(str, publicKey);

         String dencryptStr = decrypt(encryptStr, privateKey);

         System.out.println( "Encrypt : " + encryptStr );
         System.out.println( "Dencrypt : " + dencryptStr );

         String dencryptStr2 = decrypt("dDPyb7f6h0ZN/t1jbdk5BpjF6b7bCgAJXr0phSJ7facP08dXRfXiZDgnDjQ5mivOwV/NcPIo7eqr4ycunWQx4g==",
                 "MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAg8oxhsh8ZvH1ryojXI5gSk6ny0TKUVJibq7a2HuxtIH8cLPVZZD9zRCbon1uMDy6rEHlRS+7skkyoVWtU1Yx7wIDAQABAkBJ6+fLyji9JYrBLcmX6ORpyaSkh3lUE/nSS5HFS9xpepABiAUUoAv/U0w/a/ljiMUntxl9k5iPfDxm6xAnThEBAiEA0G/48jh9yxQQUL5A3Pssx1lFTifflev412cc5u7noT8CIQCh3MuOIEf0KWDt41f45GAPguz7ee2Miw7PpSNjQ0uTUQIgWvoUobywgzwdpvBzpUBomhZH3sYem/RkJ7iU7+Mk7McCIEgAcOgzQe7B7WVFCWAlLvoXcpXXQi2PujHyMtC4IclRAiEApFFDNUqmNrwIbBg0BhYFOOi4u3DoVCWPPUwptJ5eVQ0=");


         System.out.println( "通过密钥解密 ： " + dencryptStr2);

    }


}