使用数字证书进行签名和加密解密

package com.jiaoyiping.passwordmanager.pki;

import org.apache.commons.codec.binary.Hex;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;

/**
* 签名和验证签名
*/
public class TestSign {
//证书密码
private static final String PASSWORD = "123456";
//证书别名
private static final String ALIAS = "test";

public static void main(String[] args) throws Exception {

KeyStore keyStore = KeyStore.getInstance("PKCS12");
keyStore.load(new FileInputStream("D:\test.p12"), PASSWORD.toCharArray());
Certificate x509Certificate = keyStore.getCertificate(ALIAS);

encrypt(x509Certificate.getPublicKey(), (PrivateKey) keyStore.getKey(ALIAS, PASSWORD.toCharArray()));
System.out.println("==============================================================================");
sign(keyStore);
}

/**
* 签名和验证签名
*
* @throws Exception
*/
public static void sign(KeyStore keyStore) throws Exception {

X509Certificate x509Certificate = (X509Certificate) keyStore.getCertificate(ALIAS);
//需要签名的信息的内容
String message = "中国移动通信研究院";
//获取CA证书私钥
PrivateKey priKey = (PrivateKey) keyStore.getKey(ALIAS, PASSWORD.toCharArray());
System.out.println("私钥:" + Hex.encodeHexString(priKey.getEncoded()));

//用私钥签名
Signature signature = Signature.getInstance("NONEwithRSA");
signature.initSign(priKey);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
DataOutputStream dataOutputStream = new DataOutputStream(byteArrayOutputStream);
dataOutputStream.writeUTF(message);
signature.update(byteArrayOutputStream.toByteArray());
String result = Hex.encodeHexString(signature.sign());
System.out.println("签名之后的内容:" + result);

//用公钥来验证签名
Signature signature1 = Signature.getInstance("NONEwithRSA");
signature1.initVerify(x509Certificate.getPublicKey());
System.out.println("公钥:" + Hex.encodeHexString(x509Certificate.getPublicKey().getEncoded()));
ByteArrayOutputStream byteArrayOutputStream1 = new ByteArrayOutputStream();
DataOutputStream dataOutputStream1 = new DataOutputStream(byteArrayOutputStream1);
dataOutputStream1.writeUTF(message);
signature1.update(byteArrayOutputStream1.toByteArray());

System.out.println("验证结果: " + signature1.verify(Hex.decodeHex(result.toCharArray())));
}

/**
* 加密和解密
*
* @param publicKey
* @param privateKey
* @throws Exception
*/
public static void encrypt(PublicKey publicKey, PrivateKey privateKey) throws Exception {

String input = "慧与(中国)有限公司";
Cipher cipher = Cipher.getInstance("RSA");
RSAPublicKey pubKey = (RSAPublicKey) publicKey;
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey;
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] cipherText = cipher.doFinal(input.getBytes());
//加密后的内容
System.out.println("加密之后的内容:" + Hex.encodeHexString(cipherText));

//解密
cipher.init(Cipher.DECRYPT_MODE, rsaPrivateKey);
byte[] plainText = cipher.doFinal(cipherText);
System.out.println("解密之后的内容 : " + new String(plainText));

}

}