Java实现RSA算法的方法详解

package com.imooc.security.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;public class ImoocRSA {  private static String src = "cakin24 security rsa";  public static void main(String[] args) {    jdkRSA();  }  public static void jdkRSA() {    try {      //1.初始化密钥      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.私钥加密、公钥解密――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(src.getBytes());      System.out.println("私钥加密、公钥解密――加密 : " + Base64.encodeBase64String(result));      //3.私钥加密、公钥解密――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("私钥加密、公钥解密――解密：" + new String(result));      //4.公钥加密、私钥解密――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(src.getBytes());      System.out.println("公钥加密、私钥解密――加密 : " + Base64.encodeBase64String(result));      //5.公钥加密、私钥解密――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("公钥加密、私钥解密――解密：" + new String(result));    } catch (Exception e) {      e.printStackTrace();    }  }}