import javax.crypto.Cipher;
import java.math.BigInteger;
import java.security.*;
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;
* RSA
* @author wst 2021年8月5日 上午11:28:32
*
*/
public class RSAUtils {
* 密钥长度 于原文长度对应 以及越长速度越慢
*/
private final static int KEY_SIZE = 2048;
* 用于封装随机产生的公钥与私钥
*/
private static Map<Integer, String> keyMap = new HashMap<Integer, String>();
* 随机生成密钥对
*/
public static void genKeyPair() throws NoSuchAlgorithmException {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
keyPairGen.initialize(KEY_SIZE, new SecureRandom());
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
String publicKeyString = Base64.getEncoder().encodeToString(publicKey.getEncoded());
String privateKeyString = Base64.getEncoder().encodeToString(privateKey.getEncoded());
keyMap.put(0, publicKeyString);
keyMap.put(1, privateKeyString);
}
* RSA公钥加密
*
* @param str 加密字符串
* @param publicKey 公钥
* @return 密文
* @throws Exception 加密过程中的异常信息
*/
public static String encrypt(String str, String publicKey) throws Exception {
byte[] decoded = Base64.getDecoder().decode(publicKey);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
String outStr = Base64.getEncoder().encodeToString(cipher.doFinal(str.getBytes("ASCII")));
return outStr;
}
* RSA私钥解密
*
* @param str 加密字符串
* @param privateKey 私钥
* @return 明文
* @throws Exception 解密过程中的异常信息
*/
public static String decrypt(String str, String privateKey) throws Exception {
byte[] inputByte = Base64.getDecoder().decode(str);
byte[] decoded = Base64.getDecoder().decode(privateKey);
RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, priKey);
String outStr = new String(cipher.doFinal(inputByte));
return outStr;
}
* RSA私钥解密
*
* @param s 加密字符串
* @return MD5密文
* @throws Exception 解密过程中的异常信息
*/
public static String GetMD5tring(String s) {
byte[] secretBytes = null;
try {
secretBytes = MessageDigest.getInstance("md5").digest(s.getBytes());
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("没有这个md5算法!");
}
String md5code = new BigInteger(1, secretBytes).toString(16);
for (int i = 0; i < 32 - md5code.length(); i++) {
md5code = "0" + md5code;
}
return md5code;
}
public static void main(String[] args) throws Exception {
long temp = System.currentTimeMillis();
genKeyPair();
System.out.println("公钥:" + keyMap.get(0));
System.out.println("私钥:" + keyMap.get(1));
System.out.println("生成密钥消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
String message = "RSA测试ABCD~!@#$";
System.out.println("原文:" + message);
temp = System.currentTimeMillis();
String messageEn = encrypt(message, keyMap.get(0));
System.out.println("密文:" + messageEn);
System.out.println("加密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
temp = System.currentTimeMillis();
String messageDe = decrypt(messageEn, keyMap.get(1));
System.out.println("解密:" + messageDe);
System.out.println("解密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
}
}