java中常用的对称加密与非对称加密
目录
- 特殊说明
- 对称机密
- DES
- 3DES
- AES
- 非对称机密
- RSA
特殊说明
所有的算法都有main方法，可直接运行
对称机密
同一个秘钥
DES
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
/**
* 对称加密 【DES】
*
* @author it
*/
public class DESUtil {
private static final String KEY_ALGORITHM = "DES";
private static final String DEFAULT_CIPHER_ALGORITHM = "DES/ECB/PKCS5Padding";// 默认的加密算法
/**
* DES 加密操作
*
* @return 返回Base64转码后的加密数据
*/
public static String encrypt(String content, String key) {
try {
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器
byte[] byteContent = content.getBytes("utf-8");
cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));// 初始化为加密模式的密码器
byte[] result = cipher.doFinal(byteContent);// 加密
return Base64.getEncoder().encodeToString(result);// 通过Base64转码返回
} catch (Exception ex) {
Logger.getLogger(DESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* DES 解密操作
*/
public static String decrypt(String content, String key) {
try {
// 实例化
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
// 使用密钥初始化，设置为解密模式
cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));
// 执行操作
byte[] result = cipher.doFinal(Base64.getDecoder().decode(content));
return new String(result, "utf-8");
} catch (Exception ex) {
Logger.getLogger(DESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* 生成加密秘钥
*
* @return
*/
private static SecretKeySpec getSecretKey(final String key) {
// 返回生成指定算法密钥生成器的 KeyGenerator 对象
KeyGenerator kg = null;
try {
kg = KeyGenerator.getInstance(KEY_ALGORITHM);
// DES 要求密钥长度为 56
kg.init(56, new SecureRandom(key.getBytes()));
// 生成一个密钥
SecretKey secretKey = kg.generateKey();
return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为DES专用密钥
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(DESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
public static void main(String[] args) {
String content = "hello,您好，李四，我喜欢你，这个内容加密了，别人不知道的";
String key = "sde@5f98H*^hsff%dfs$r344&df8543*er";
System.out.println("原始内容:" + content);
String s1 = DESUtil.encrypt(content, key);
System.out.println("加密后:" + s1);
System.out.println("解密后:" + DESUtil.decrypt(s1, key));
}
}
3DES
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
/**
* 对称加密 【3DES】
*
* @author it
*/
public class TripDESUtil {
private static final String KEY_ALGORITHM = "DESede";
private static final String DEFAULT_CIPHER_ALGORITHM = "DESede/ECB/PKCS5Padding";// 默认的加密算法
/**
* DESede 加密操作
*
* @return 返回Base64转码后的加密数据
*/
public static String encrypt(String content, String key) {
try {
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器
byte[] byteContent = content.getBytes("utf-8");
cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));// 初始化为加密模式的密码器
byte[] result = cipher.doFinal(byteContent);// 加密
return Base64.getEncoder().encodeToString(result);// 通过Base64转码返回
} catch (Exception ex) {
Logger.getLogger(TripDESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* DESede 解密操作
*/
public static String decrypt(String content, String key) {
try {
// 实例化
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
// 使用密钥初始化，设置为解密模式
cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));
// 执行操作
byte[] result = cipher.doFinal(Base64.getDecoder().decode(content));
return new String(result, "utf-8");
} catch (Exception ex) {
Logger.getLogger(TripDESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* 生成加密秘钥
*/
private static SecretKeySpec getSecretKey(final String key) {
// 返回生成指定算法密钥生成器的 KeyGenerator 对象
KeyGenerator kg = null;
try {
kg = KeyGenerator.getInstance(KEY_ALGORITHM);
// DESede
kg.init(new SecureRandom(key.getBytes()));
// 生成一个密钥
SecretKey secretKey = kg.generateKey();
return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为DESede专用密钥
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(TripDESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
public static void main(String[] args) {
String content = "hello,您好，李四，我喜欢你，这个内容加密了，别人不知道的";
String key = "sde@5f98H*^hsff%dfs$r344&df8543*er";
System.out.println("原始内容:" + content);
String s1 = TripDESUtil.encrypt(content, key);
System.out.println("加密后:" + s1);
System.out.println("解密后:" + TripDESUtil.decrypt(s1, key));
}
}
AES
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
/**
* 对称加密 【AES】
*
* @author it
*/
public class AESUtil {
private static final String KEY_ALGORITHM = "AES";
private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";// 默认的加密算法
/**
* AES 加密操作
*
* @return 返回Base64转码后的加密数据
*/
public static String encrypt(String content, String key) {
try {
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器
byte[] byteContent = content.getBytes("utf-8");
cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));// 初始化为加密模式的密码器
byte[] result = cipher.doFinal(byteContent);// 加密
return Base64.getEncoder().encodeToString(result);// 通过Base64转码返回
} catch (Exception ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* AES 解密操作
*/
public static String decrypt(String content, String key) {
try {
// 实例化
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
// 使用密钥初始化，设置为解密模式
cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));
// 执行操作
byte[] result = cipher.doFinal(Base64.getDecoder().decode(content));
return new String(result, "utf-8");
} catch (Exception ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* 生成加密秘钥
*/
private static SecretKeySpec getSecretKey(final String key) {
// 返回生成指定算法密钥生成器的 KeyGenerator 对象
KeyGenerator kg = null;
try {
kg = KeyGenerator.getInstance(KEY_ALGORITHM);
// AES 要求密钥长度为 128
kg.init(128, new SecureRandom(key.getBytes()));
// 生成一个密钥
SecretKey secretKey = kg.generateKey();
return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为AES专用密钥
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
public static void main(String[] args) {
String content = "hello,您好，李四，我喜欢你，这个内容加密了，别人不知道的";
String key = "sde@5f98H*^hsff%dfs$r344&df8543*er";
System.out.println("原始内容:" + content);
String s1 = AESUtil.encrypt(content, key);
System.out.println("加密后:" + s1);
System.out.println("解密后:" + AESUtil.decrypt(s1, key));
}
}
非对称机密
RSA
import java.io.ByteArrayOutputStream;
import java.nio.charset.Charset;
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.Signature;
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;
/**
*
* RSA公钥/私钥/签名工具包
*
*
* 罗纳德·李维斯特（Ron [R]ivest）、阿迪·萨莫尔（Adi [S]hamir）和伦纳德·阿德曼（Leonard [A]dleman）
*
*
* 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式
* 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，
* 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
*
*
*/
public class RSAUtils {
/**
* 加密算法RSA
*/
public static final String KEY_ALGORITHM = "RSA";
/**
* 签名算法
*/
public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
/**
* 获取公钥的key
*/
private static final String PUBLIC_KEY = "RSAPublicKey";
/**
* 获取私钥的key
*/
private static final String PRIVATE_KEY = "RSAPrivateKey";
/**
* RSA最大加密明文大小
*/
private static final int MAX_ENCRYPT_BLOCK = 117;
/**
* RSA最大解密密文大小
*/
private static final int MAX_DECRYPT_BLOCK = 128;
/**
*
* 用私钥对信息生成数字签名
*
*
* @param data
* 已加密数据
* @param privateKey
* 私钥(BASE64编码)
*
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(data);
return Base64Utils.encode(signature.sign());
}
/**
*
* 校验数字签名
*
*
* @param data
* 已加密数据
* @param publicKey
* 公钥(BASE64编码)
* @param sign
* 数字签名
*
* @return
* @throws Exception
*
*/
public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(data);
return signature.verify(Base64Utils.decode(sign));
}
/**
*
* 私钥解密
*
*
* @param encryptedData
* 已加密数据
* @param privateKey
* 私钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/**
*
* 公钥解密
*
*
* @param encryptedData
* 已加密数据
* @param publicKey
* 公钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/**
*
* 公钥加密
*
*
* @param data
* 源数据
* @param publicKey
* 公钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
// 对数据加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/**
*
* 私钥加密
*
*
* @param data
* 源数据
* @param privateKey
* 私钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/**
*
* 生成密钥对(公钥和私钥)
*
*
* @return
* @throws Exception
*/
public static Map<String, Object> genKeyPair() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/**
*
* 获取私钥
*
*
* @param keyMap
* 密钥对
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);
return Base64Utils.encode(key.getEncoded());
}
/**
*
* 获取公钥
*
*
* @param keyMap
* 密钥对
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return Base64Utils.encode(key.getEncoded());
}
public static void main(String[] args) throws Exception {
Map<String, Object> keyPairs = RSAUtils.genKeyPair();
String privateKey = RSAUtils.getPrivateKey(keyPairs);
String publicKey = RSAUtils.getPublicKey(keyPairs);
System.out.println("私钥：" + privateKey);
System.out.println("公钥：" + publicKey);
// 公钥加密，私钥解密
String content = "hello,您好，李四，我喜欢你，这个内容加密了，别人不知道的";
byte[] encryptedData = RSAUtils.encryptByPublicKey(content.getBytes(Charset.defaultCharset()), publicKey);
byte[] decryptedData = RSAUtils.decryptByPrivateKey(encryptedData, privateKey);
System.out.println(new String(decryptedData));
// 数字签名验证
// 私钥签名，生产一个key
String sign = RSAUtils.sign(encryptedData, privateKey);
// 公钥验证
boolean verify = RSAUtils.verify(encryptedData, publicKey, sign);
System.out.println("内容是否安全：" + verify);
// 私钥加密，公钥解密
content = "滚你妈的";
byte[] encryptedData2 = RSAUtils.encryptByPrivateKey(content.getBytes(Charset.defaultCharset()), privateKey);
byte[] decryptedData2 = RSAUtils.decryptByPublicKey(encryptedData2, publicKey);
System.out.println(new String(decryptedData2));
}
}
附加工具类base64
import java.util.Base64;
public class Base64Utils {
/**
*
* BASE64字符串解码为二进制数据
*
*
* @param base64
* @return
* @throws Exception
*/
public static byte[] decode(String base64) throws Exception {
return Base64.getDecoder().decode(base64.getBytes());
}
/**
*
* 二进制数据编码为BASE64字符串
*
*
* @param bytes
* @return
* @throws Exception
*/
public static String encode(byte[] bytes) throws Exception {
return new String(Base64.getEncoder().encode(bytes));
}
}