Java加密算法笔记–RSA算法实现
import java.security.Key;
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.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;
/**
* 1、公钥加密，私钥解密用于信息加密
* 2、私钥加密，公钥解密用于数字签名
*/
public class RSA {
/**
* 测试方法
*/
public static void main(String[] args) {
// Map<String, Object> map = new HashMap<String, Object>();
// map = RSA.init();
// System.out.println("公钥："+RSA.getPublicKey(map));
// System.out.println("私钥："+RSA.getPrivateKey(map));
//由前四行代码获得公、私密钥
String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCLNbmKl9/gLn7Bef/xtUkshC1WyrLZLRpXCcFYR1gQi0isWsZBTicC4efBOkkNG3r+1ue0gvtuU/tjREFGf4Y7HaKHGb5tNCOlMNeNjM5YLRwLFqrUSsQyD4rj4eua1ltearr24R0HilnTvnQm6Z/UY0s21vdOUFQBPY0GNAa+0wIDAQAB";
String privateKey = "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";
String str = "你好goldlone, RSA!";
// 公钥加密，私钥解密
String enStr1 = RSA.encryptByPublic(str, publicKey);
System.out.println("公钥加密后："+enStr1);
String deStr1 = RSA.decryptByPrivate(enStr1, privateKey);
System.out.println("私钥解密后："+deStr1);
// 私钥加密，公钥解密
String enStr2 = RSA.encryptByPrivate(str, privateKey);
System.out.println("私钥加密后："+enStr2);
String deStr2 = RSA.decryptByPublic(enStr2, publicKey);
System.out.println("公钥解密后："+deStr2);
// 产生签名
String sign = sign(enStr2, privateKey);
System.out.println("签名:"+sign);
// 验证签名
boolean status = verify(enStr2, publicKey, sign);
System.out.println("状态:"+status);
}
//定义加密方式
public static final String KEY_RSA = "RSA";
//定义公钥关键词
public static final String KEY_RSA_PUBLICKEY = "RSAPublicKey";
//定义私钥关键词
public static final String KEY_RSA_PRIVATEKEY = "RSAPrivateKey";
//定义签名算法
private final static String KEY_RSA_SIGNATURE = "MD5withRSA";
/**
* 生成公私密钥对
*/
public static Map<String, Object> init() {
Map<String, Object> map = null;
try {
KeyPairGenerator generator = KeyPairGenerator.getInstance(KEY_RSA);
//设置密钥对的bit数，越大越安全，但速度减慢，一般使用512或1024
generator.initialize(1024);
KeyPair keyPair = generator.generateKeyPair();
// 获取公钥
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
// 获取私钥
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
// 将密钥对封装为Map
map = new HashMap<String, Object>();
map.put(KEY_RSA_PUBLICKEY, publicKey);
map.put(KEY_RSA_PRIVATEKEY, privateKey);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return map;
}
/**
* 获取Base64编码的公钥字符串
*/
public static String getPublicKey(Map<String, Object> map) {
String str = "";
Key key = (Key) map.get(KEY_RSA_PUBLICKEY);
str = encryptBase64(key.getEncoded());
return str;
}
/**
* 获取Base64编码的私钥字符串
*/
public static String getPrivateKey(Map<String, Object> map) {
String str = "";
Key key = (Key) map.get(KEY_RSA_PRIVATEKEY);
str = encryptBase64(key.getEncoded());
return str;
}
/**
* BASE64 解码
* @param key 需要Base64解码的字符串
* @return 字节数组
*/
public static byte[] decryptBase64(String key) {
return Base64.getDecoder().decode(key);
}
/**
* BASE64 编码
* @param key 需要Base64编码的字节数组
* @return 字符串
*/
public static String encryptBase64(byte[] key) {
return new String(Base64.getEncoder().encode(key));
}
/**
* 公钥加密
* @param encryptingStr
* @param publicKey
* @return
*/
public static String encryptByPublic(String encryptingStr, String publicKeyStr){
try {
// 将公钥由字符串转为UTF-8格式的字节数组
byte[] publicKeyBytes = decryptBase64(publicKeyStr);
// 获得公钥
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
// 取得待加密数据
byte[] data = encryptingStr.getBytes("UTF-8");
KeyFactory factory;
factory = KeyFactory.getInstance(KEY_RSA);
PublicKey publicKey = factory.generatePublic(keySpec);
// 对数据加密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
// 返回加密后由Base64编码的加密信息
return encryptBase64(cipher.doFinal(data));
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 私钥解密
* @param encryptedStr
* @param privateKey
* @return
*/
public static String decryptByPrivate(String encryptedStr, String privateKeyStr){
try {
// 对私钥解密
byte[] privateKeyBytes = decryptBase64(privateKeyStr);
// 获得私钥
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
// 获得待解密数据
byte[] data = decryptBase64(encryptedStr);
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
PrivateKey privateKey = factory.generatePrivate(keySpec);
// 对数据解密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateKey);
// 返回UTF-8编码的解密信息
return new String(cipher.doFinal(data), "UTF-8");
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 私钥加密
* @param encryptingStr
* @param privateKey
* @return
*/
public static String encryptByPrivate(String encryptingStr, String privateKeyStr){
try {
byte[] privateKeyBytes = decryptBase64(privateKeyStr);
// 获得私钥
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
// 取得待加密数据
byte[] data = encryptingStr.getBytes("UTF-8");
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
PrivateKey privateKey = factory.generatePrivate(keySpec);
// 对数据加密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
// 返回加密后由Base64编码的加密信息
return encryptBase64(cipher.doFinal(data));
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 公钥解密
* @param encryptedStr
* @param privateKey
* @return
*/
public static String decryptByPublic(String encryptedStr, String publicKeyStr){
try {
// 对公钥解密
byte[] publicKeyBytes = decryptBase64(publicKeyStr);
// 取得公钥
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
// 取得待加密数据
byte[] data = decryptBase64(encryptedStr);
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
PublicKey publicKey = factory.generatePublic(keySpec);
// 对数据解密
Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicKey);
// 返回UTF-8编码的解密信息
return new String(cipher.doFinal(data), "UTF-8");
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 用私钥对加密数据进行签名
* @param encryptedStr
* @param privateKey
* @return
*/
public static String sign(String encryptedStr, String privateKey) {
String str = "";
try {
//将私钥加密数据字符串转换为字节数组
byte[] data = encryptedStr.getBytes();
// 解密由base64编码的私钥
byte[] bytes = decryptBase64(privateKey);
// 构造PKCS8EncodedKeySpec对象
PKCS8EncodedKeySpec pkcs = new PKCS8EncodedKeySpec(bytes);
// 指定的加密算法
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
// 取私钥对象
PrivateKey key = factory.generatePrivate(pkcs);
// 用私钥对信息生成数字签名
Signature signature = Signature.getInstance(KEY_RSA_SIGNATURE);
signature.initSign(key);
signature.update(data);
str = encryptBase64(signature.sign());
} catch (Exception e) {
e.printStackTrace();
}
return str;
}
/**
* 校验数字签名
* @param encryptedStr
* @param publicKey
* @param sign
* @return 校验成功返回true，失败返回false
*/
public static boolean verify(String encryptedStr, String publicKey, String sign) {
boolean flag = false;
try {
//将私钥加密数据字符串转换为字节数组
byte[] data = encryptedStr.getBytes();
// 解密由base64编码的公钥
byte[] bytes = decryptBase64(publicKey);
// 构造X509EncodedKeySpec对象
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(bytes);
// 指定的加密算法
KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
// 取公钥对象
PublicKey key = factory.generatePublic(keySpec);
// 用公钥验证数字签名
Signature signature = Signature.getInstance(KEY_RSA_SIGNATURE);
signature.initVerify(key);
signature.update(data);
flag = signature.verify(decryptBase64(sign));
} catch (Exception e) {
e.printStackTrace();
}
return flag;
}
}运行结果：
公钥加密后：TWWRIh4NIqslqWtT/1R4HbIrpXQRUU5Q4oJxa60+k11TINsxZVr9ox+aPZkjtlKRa5oaUqIsZysOwn4kxiDe6ielxUjQENz/lWc8pp5YpVR5INR3qP33aVXFHiqYHvkkXbhaDUlb4J0jYZDKLPgCUe3aG5vQN+DfdFcYnW2K9+8=
私钥解密后：你好goldlone, RSA!
私钥加密后：iND60pcTmbQqx0BcmfXtw+HY8XkCUFS9ifhRqL9IZpeimdRMlB3hPRK6m5ojmG+c836eX6+j1OYsmtp6ZfGbEoYCsiD1II+Xsx9vOfv42uf8yN3jlXXs4L5ybN65oB/LsuSsIvg1df72HU59mbPEQAqP5AHfnHImtRqN9DtE/Dg=
公钥解密后：你好goldlone, RSA!
签名:MGZDwjkFGs94MXrwcnhtcq97dnh5g0rGVcL0PuMgsOQfDYSpK129BlpoKCaHrqgXieg9ZfLaCFXaiQi74emAtGIPxODHl4DDiz7UEDABGZ5P+kQwHk0QTOVg5cBpwKkkdz3qka99ECaz1+ufAPX32wc4jcj1XcQPEj2gbnYsyPo=
状态:true
