书籍是全世界的营养品。生活里没有书籍，就好像没有阳光；智慧里没有书籍，就好像鸟儿没有翅膀。
需求：前端登录的usernamepassword，password必需加密。但不可使用MD5，由于后台要检測password的复杂度，那么在保证安全的前提下将password传到后台呢，答案就是使用RSA非对称加密算法解决 。
须要依赖 commons-codec 包
RSACoder.java
import org.apache.commons.codec.binary.Base64;import javax.crypto.Cipher;import java.security.*;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;import java.util.HashMap;import java.util.Map;/**
* Created by lake on 17-4-12.
*/public class RSACoder {
public static final String KEY_ALGORITHM = "RSA"; public static final String SIGNATURE_ALGORITHM = "MD5withRSA"; private static final String PUBLIC_KEY = "RSAPublicKey"; private static final String PRIVATE_KEY = "RSAPrivateKey"; public static byte[] decryptBASE64(String key) { return Base64.decodeBase64(key);
} public static String encryptBASE64(byte[] bytes) { return Base64.encodeBase64String(bytes);
} /**
* 用私钥对信息生成数字签名
*
* @param data 加密数据
* @param privateKey 私钥
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception { // 解密由base64编码的私钥
byte[] keyBytes = decryptBASE64(privateKey); // 构造PKCS8EncodedKeySpec对象
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); // KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); // 取私钥匙对象
PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec); // 用私钥对信息生成数字签名
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(priKey);
signature.update(data); return encryptBASE64(signature.sign());
} /**
* 校验数字签名
*
* @param data 加密数据
* @param publicKey 公钥
* @param sign 数字签名
* @return 校验成功返回true 失败返回false
* @throws Exception
*/
public static boolean verify(byte[] data, String publicKey, String sign)
throws Exception { // 解密由base64编码的公钥
byte[] keyBytes = decryptBASE64(publicKey); // 构造X509EncodedKeySpec对象
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); // KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); // 取公钥匙对象
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(pubKey);
signature.update(data); // 验证签名是否正常
return signature.verify(decryptBASE64(sign));
} public static byte[] decryptByPrivateKey(byte[] data, String key) throws Exception{ // 对密钥解密
byte[] keyBytes = decryptBASE64(key); // 取得私钥
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec); // 对数据解密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateKey); return cipher.doFinal(data);
} /**
* 解密<br>
* 用私钥解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(String data, String key) throws Exception { return decryptByPrivateKey(decryptBASE64(data),key);
} /**
* 解密<br>
* 用公钥解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptByPublicKey(byte[] data, String key) throws Exception { // 对密钥解密
byte[] keyBytes = decryptBASE64(key); // 取得公钥
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicKey = keyFactory.generatePublic(x509KeySpec); // 对数据解密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicKey); return cipher.doFinal(data);
} /**
* 加密<br>
* 用公钥加密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encryptByPublicKey(String data, String key) throws Exception { // 对公钥解密
byte[] keyBytes = decryptBASE64(key); // 取得公钥
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicKey = keyFactory.generatePublic(x509KeySpec); // 对数据加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicKey); return cipher.doFinal(data.getBytes());
} /**
* 加密<br>
* 用私钥加密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encryptByPrivateKey(byte[] data, String key) throws Exception { // 对密钥解密
byte[] keyBytes = decryptBASE64(key); // 取得私钥
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec); // 对数据加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateKey); return cipher.doFinal(data);
} /**
* 取得私钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Key> keyMap)
throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY); return encryptBASE64(key.getEncoded());
} /**
* 取得公钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Key> keyMap)
throws Exception {
Key key = keyMap.get(PUBLIC_KEY); return encryptBASE64(key.getEncoded());
} /**
* 初始化密钥
*
* @return
* @throws Exception
*/
public static Map<String, Key> initKey() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator
.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
Map<String, Key> keyMap = new HashMap(2);
keyMap.put(PUBLIC_KEY, keyPair.getPublic());// 公钥
keyMap.put(PRIVATE_KEY, keyPair.getPrivate());// 私钥
return keyMap;
}
}
測试类
RSACoderTest.java
import org.junit.Before;import org.junit.Test;import java.security.Key;import java.util.Map;import static org.junit.Assert.assertEquals;import static org.junit.Assert.assertTrue;/**
* Created by lake on 17-4-12.
*/public class RSACoderTest {
private String publicKey; private String privateKey; @Before
public void setUp() throws Exception {
Map<String, Key> keyMap = RSACoder.initKey();
publicKey = RSACoder.getPublicKey(keyMap);
privateKey = RSACoder.getPrivateKey(keyMap);
System.err.println("公钥: \n\r" + publicKey);
System.err.println("私钥： \n\r" + privateKey);
} @Test
public void test() throws Exception {
System.err.println("公钥加密——私钥解密");
String inputStr = "abc"; byte[] encodedData = RSACoder.encryptByPublicKey(inputStr, publicKey); byte[] decodedData = RSACoder.decryptByPrivateKey(encodedData,
privateKey);
String outputStr = new String(decodedData);
System.err.println("加密前: " + inputStr + "\n\r" + "解密后: " + outputStr);
assertEquals(inputStr, outputStr);
} @Test
public void testSign() throws Exception {
System.err.println("私钥加密——公钥解密");
String inputStr = "sign"; byte[] data = inputStr.getBytes(); byte[] encodedData = RSACoder.encryptByPrivateKey(data, privateKey); byte[] decodedData = RSACoder.decryptByPublicKey(encodedData, publicKey);
String outputStr = new String(decodedData);
System.err.println("加密前: " + inputStr + "\n\r" + "解密后: " + outputStr);
assertEquals(inputStr, outputStr);
System.err.println("私钥签名——公钥验证签名"); // 产生签名
String sign = RSACoder.sign(encodedData, privateKey);
System.err.println("签名:" + sign); // 验证签名
boolean status = RSACoder.verify(encodedData, publicKey, sign);
System.err.println("状态:" + status);
assertTrue(status);
}
}
依赖 jsencrypt 项目
<script src="bin/jsencrypt.min.js"></script><script type="text/javascript">
var encrypt = new JSEncrypt();
encrypt.setPublicKey('java生成的公钥'); var encrypted = encrypt.encrypt('加密的字符串');</script>
前端生成加密的字符串encrypted，传到后台，java使用私钥进行解密就可以。
