使用java 的keytool生成RSA 公钥 私钥 （含代码验证）

keytool的使用

keytool程序由JDK提供，可以生成、查看证书和key.而keystore是key的容器，可以容纳多个key及相关信息。

每一条key由一个别名alias引用。可以把keystore中的key导出为证书文件.cer。显然，用keytool生成的.cer

是未经CA签名的证书。

添加一个Key

keytool -genkey -alias acosta -keyalg RSA -keysize 1024 -keystore acosta.keystore

查看keystore中所有的Key

keytool -list -keystore acosta.keystore

查看keystore中指定的一条记录

keytool -list -v -alias acosta -keystore acosta.keystore

将keystore中的key导出成证书文件

keytool -list -v -alias acosta -keystore acosta.keystore  -export -file acosta.cer

使用java代码验证

代码如下

RSAUtil.java

package com.cn.costa.testdemo.RSA;

import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.Key;
import java.security.KeyFactory;
import java
4000
.security.KeyPair;
import java.security.KeyPairGenerator;
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.CertificateFactory;
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;

/**
* <p>
* RSA公钥/私钥/签名工具包
* </p>
* <p>
*
* </p>
* <p>
* 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<br/>
* 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，<br/>
* 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
* </p>
*
* @author wechart
* @date 2016-4-26
* @version 1.0
*/
public class RSAUtils {

public static final String KEY_ALGORITHM = "RSA";                   //加密算法RSA

public static final String SIGNATURE_ALGORITHM = "MD5withRSA";      //签名算法

private static final String PUBLIC_KEY = "RSAPublicKey";            //获取公钥的KEY

private static final String PRIVATE_KEY = "RSAPrivateKey";          //获取私钥的KEY

private static final int MAX_ENCRYPT_BLOCK = 117;                   //RSA最大加密明文大小

private static final int MAX_DECRYPT_BLOCK = 128;                   //RSA最大解密密文大小

/**
* <p>
* 生成密钥对(公钥和私钥)
* </p>
*
* @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;
}

/**
* <p>
* 用私钥对信息生成数字签名
* </p>
*
* @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());
}

/**
* <p>
* 校验数字签名
* </p>
*
* @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));
}

/** *//**
* <P>
* 私钥解密
* </p>
*
* @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;
}

/** *//**
* <p>
* 公钥解密
* </p>
*
* @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;
}

/** *//**
* <p>
* 公钥加密
* </p>
*
* @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;
}

/**
* <p>
* 私钥加密
* </p>
*
* @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) {

eef7
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;
}

/**
* <p>
* 获取私钥
* </p>
*
* @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());
}

/**
* <p>
* 获取公钥
* </p>
*
* @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 PublicKey loadPublicKeyByFile(String filepath) throws Exception {
try {
//通过证书,获取公钥
CertificateFactory cf = CertificateFactory.getInstance("X.509");
Certificate c = cf.generateCertificate(new FileInputStream(filepath));
PublicKey publicKey = c.getPublicKey();
return publicKey;
} catch (IOException e) {
throw new Exception("公钥数据流读取错误");
} catch (NullPointerException e) {
throw new Exception("公钥输入流为空");
}
}

public static PrivateKey loadPrivateKeyByFile(String filepath, String alias, String password) throws Exception {
try {
KeyStore ks= KeyStore.getInstance("JKS");
ks.load(new FileInputStream(filepath), password.toCharArray());

PrivateKey privateKey = (PrivateKey)ks.getKey(alias, password.toCharArray());
return privateKey;
} catch (IOException e) {
throw new Exception("私钥数据读取错误");
} catch (NullPointerException e) {
throw new Exception("私钥输入流为空");
}
}

public static void main(String[] args){
String serverAlias = "";
String clientAlias = "acosta";

String serverPassword = "";
String clientPassword = "acosta";

//      String serverPrivateKey = "d:\\server.keystore";
//      String serverPublicKey = "d:\\server.cer";

String clientPrivateKey = "E:\\TestCER\\RSATest04\\acosta.keystore";
String clientPublicKey = "E:\\TestCER\\RSATest04\\acosta.cer";
//
//      String serverPublicString = "";
//      String serverPrivateString = "";
String clientPublicString = "";
String clientPrivateString = "";

String orgString = "{\"ret\":\"0\",\"ExpireTime\":\"2015/10/28 23:59:59\",\"rettxt\":\"OK\",\"Token\":\"69296128A59798E2D423D3B1A9F766F4\"}'";

String encryptString = "";
String decryptString = "";

//      RSAPublicKey srvPubKey = null;
RSAPublicKey cltPubKey = null;
//      RSAPrivateKey srvPriKey = null;
RSAPrivateKey cltPriKey = null;

try{
//1- 客户端公钥
cltPubKey = (RSAPublicKey) RSAUtils.loadPublicKeyByFile(clientPublicKey);

//2- 客户端私钥
cltPriKey = (RSAPrivateKey) RSAUtils.loadPrivateKeyByFile(clientPrivateKey, clientAlias, clientPassword);

//          //3- 服务端公钥
//          srvPubKey = (RSAPublicKey) RSAUtils.loadPublicKeyByFile(serverPublicKey);
//
//          //4- 服务端私钥
//          srvPriKey = (RSAPrivateKey) RSAUtils.loadPrivateKeyByFile(serverPrivateKey, serverAlias, serverPassword);

System.out.println("\nclientPublicString:\n"+Base64Utils.encode(cltPubKey.getEncoded())+"\n");
System.out.println("\nclientPrivateString:\n"+Base64Utils.encode(cltPriKey.getEncoded())+"\n");
//          System.out.println("\nserverPublicString:\n"+Base64Utils.encode(srvPubKey.getEncoded())+"\n");
//          System.out.println("\nserverPrivateString:\n"+Base64Utils.encode(srvPriKey.getEncoded())+"\n");
}catch(Exception e){
e.printStackTrace();
}

//      System.out.println("\n=============================== Step-1:客户端私钥加密-服务端公钥解密\n");
//      //客户端私钥加密-服务端公钥解密
//      try{
//          byte[] data = orgString.getBytes();
//
//          byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(cltPriKey.getEncoded()));
//          encryptString = new String(encodedData);
//
//          byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(srvPubKey.getEncoded()));
//          decryptString = new String(decodedData);
//
//          System.out.println("orginalString:"+orgString);
//          System.out.println("encrypString:"+encryptString);
//          System.out.println("decryptString:"+decryptString);
//      }catch(Exception e){
//          System.err.println("Step-1 解密失败!");
//      }
//
//      System.out.println("\n=============================== Step-2:服务端私钥加密-客户端公钥解密\n");
//      //服务端私钥加密-客户端公钥解密
//      try{
//
//
//          byte[] data = orgString.getBytes();
//
//          byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(srvPriKey.getEncoded()));
//          encryptString = new String(encodedData);
//
//          byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(cltPubKey.getEncoded()));
//          decryptString = new String(decodedData);
//
//          System.out.println("orginalString:"+orgString);
//          System.out.println("encrypString:"+encryptString);
//          System.out.println("decryptString:"+decryptString);
//      }catch(Exception e){
//          System.err.println("Step-2 解密失败!");
//      }

System.out.println("\n=============================== Step-3:客户端私钥加密-客户端公钥解密\n");

String orgString2 = "";
//客户端私钥加密-客户端公钥解密
try{
byte[] data = orgString.getBytes();

byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(cltPriKey.getEncoded()));
encryptString = new String(encodedData);

byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(cltPubKey.getEncoded()));
decryptString = new String(decodedData);

System.out.println("orginalString:"+orgString);
System.out.println("encrypString:"+encryptString);
System.out.println("decryptString:"+decryptString);
}catch(Exception e){
System.err.println("Step-3  解密失败!");
}
//
//      System.out.println("\n=============================== Step-4:服务端私钥加密-服务端公钥解密\n");
//      //服务端私钥加密-服务端公钥解密
//      try{
//
//          byte[] data = orgString.getBytes();
//
//          byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(srvPriKey.getEncoded()));
//          encryptString = new String(encodedData);
//
//          byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(srvPubKey.getEncoded()));
//          decryptString = new String(decodedData);
//
//          System.out.println("orginalString:"+orgString);
//          System.out.println("encrypString:"+encryptString);
//          System.out.println("decryptString:"+decryptString);
//      }catch(Exception e){
//          System.err.println("Step-4 解密失败!");
//      }
//
}

}

Base64Utils

package com.cn.costa.testdemo.RSA;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import Decoder.BASE64Decoder;
import Decoder.BASE64Encoder;

/** *//**
* <p>
* BASE64编码解码工具包
* </p>
* <p>
* 依赖javabase64-1.3.1.jar
* </p>
*
* @author wechat
* @date 2014-5-19
* @version 1.0
*/
public class Base64Utils {

/** *//**
* 文件读取缓冲区大小
*/
private static final int CACHE_SIZE = 1024;

/** *//**
* <p>
* BASE64字符串解码为二进制数据
* </p>
*
* @param base64
* @return
* @throws Exception
*/
public static byte[] decode(String base64) throws Exception {
BASE64Decoder decoder = new BASE64Decoder();

try {
return decoder.decodeBuffer(base64);
} catch (Exception e) {
return null;
}

}

/** *//**
* <p>
* 二进制数据编码为BASE64字符串
* </p>
*
* @param bytes
* @return
* @throws Exception
*/
public static String encode(byte[] bytes) throws Exception {
BASE64Encoder encoder = new BASE64Encoder();
return new String(encoder.encode(bytes));
}

/** *//**
* <p>
* 将文件编码为BASE64字符串
* </p>
* <p>
* 大文件慎用，可能会导致内存溢出
* </p>
*
* @param filePath 文件绝对路径
* @return
* @throws Exception
*/
public static String encodeFile(String filePath) throws Exception {
byte[] bytes = fileToByte(filePath);
return encode(bytes);
}

/** *//**
* <p>
* BASE64字符串转回文件
* </p>
*
* @param filePath 文件绝对路径
* @param base64 编码字符串
* @throws Exception
*/
public static void decodeToFile(String filePath, String base64) throws Exception {
byte[] bytes = decode(base64);
byteArrayToFile(bytes, filePath);
}

/** *//**
* <p>
* 文件转换为二进制数组
* </p>
*
* @param filePath 文件路径
* @return
* @throws Exception
*/
public static byte[] fileToByte(String filePath) throws Exception {
byte[] data = new byte[0];
File file = new File(filePath);
if (file.exists()) {
FileInputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
data = out.toByteArray();
}
return data;
}

/** *//**
* <p>
* 二进制数据写文件
* </p>
*
* @param bytes 二进制数据
* @param filePath 文件生成目录
*/
public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
InputStream in = new ByteArrayInputStream(bytes);
File destFile = new File(filePath);
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
OutputStream out = new FileOutputStream(destFile);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
}

}

需要jar包

sun.misc.BASE64Decoder.jar

FastInfoset.jar