作为常用的非对称加密算法，本篇文章大致记录一下，在java代码中如何生成RSA的密钥对以及加密解密的使用。
1、生成密钥对
public class RSAUtils {// 填充方式public static final String RSA_ALGORITHM_NOPADDING = "RSA";public static final String RSA_ALGORITHM = "RSA/ECB/PKCS1Padding";/*** 生成密钥对* @return*/public static Map<String, String> createKeyPairs() {try {KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(RSA_ALGORITHM_NOPADDING);keyPairGenerator.initialize(2048);KeyPair keyPair = keyPairGenerator.generateKeyPair();RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();return new HashMap<String, String>(){{put("publicKey", Base64.encodeBase64String(publicKey.getEncoded()));put("privateKey", Base64.encodeBase64String(privateKey.getEncoded()));}};} catch (NoSuchAlgorithmException e) {e.printStackTrace();}return null;}}
2、加密
/*** 通过公钥对数据进行加密* @param publicKeyStr* @param data* @return*/public static String encryptRSADefault(String publicKeyStr, String data) {try {KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM_NOPADDING); // 指定算法，返回keyFactory对象byte[] publicKeyByte = Base64.decodeBase64(publicKeyStr); // 或：Base64.decodeBase64(publicKeyStr.getBytes())X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(publicKeyByte); // 创建X509编码公钥规范PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec); // 根据X5090编码密钥规范产生公钥对象Cipher cipher = Cipher.getInstance(RSA_ALGORITHM_NOPADDING); // 根据算法名称，生成密码对象cipher.init(Cipher.ENCRYPT_MODE, publicKey); // 使用公钥初始化cipher对象（encrypt加密模式）byte[] encryptByte = cipher.doFinal(data.getBytes()); // 对数据进行加密return Base64.encodeBase64String(encryptByte); // 将字节数组，经过base64编码后，以US-ASCII编码输出为字符串} catch (Exception e) {e.printStackTrace();}return null;}
3、解密
public static String decryptRSADefault(String privateKeyStr, String data) {try {KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM_NOPADDING);byte[] privateKeyByte = Base64.decodeBase64(privateKeyStr);PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(privateKeyByte); // 密钥为pkcs8格式PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec); // 生成私钥对象Cipher cipher = Cipher.getInstance(RSA_ALGORITHM_NOPADDING);cipher.init(Cipher.DECRYPT_MODE, privateKey);byte[] decryptByte = cipher.doFinal(Base64.decodeBase64(data.getBytes()));return new String(decryptByte, "UTF-8");} catch (Exception e) {e.printStackTrace();}return null;}
4、测试
public static void main(String[] args) {Map<String, String> keyPairs = createKeyPairs();System.out.println("公钥：\n" + keyPairs.get("publicKey"));System.out.println("私钥：\n" + keyPairs.get("privateKey"));if (null != keyPairs) {String encryptMsg = RSAUtils.encryptRSADefault(keyPairs.get("publicKey"), "hello world");System.out.println("加密后的内容：" + encryptMsg);String decryptMsg = RSAUtils.decryptRSADefault(keyPairs.get("privateKey"), encryptMsg);System.out.println("解密后的内容：" + decryptMsg);}
输出结果：
