本文借鉴于http://blog.csdn.net/chaijunkun/article/details/7275632的博客
第一步：使用Openssl生成私钥跟公钥
由于笔者使用阿里云服务器ubuntu 16.04，自带Openssl，跳过
输入命令：openssl version -a 查询是否安装Openssl
生成1024位私钥：openssl genrsa -out rsa_private_key.pem 1024
查看生成的私钥：cat rsa_private_key.pem
根据私钥生成公钥：openssl rsa -in rsa_private_key.pem -out rsa_public_key.pem -pubout
查看生成的公钥：cat rsa_public_key.pem
私钥进行PKCS#8编码：openssl pkcs8 -topk8 -in rsa_private_key.pem -out pkcs8_rsa_private_key.pem -nocrypt
查看编码后的PKCS#8私钥：cat pkcs8_rsa_private_key.pem
验证秘钥对是否正确的代码如下：
package com.koow.test;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.io.BufferedReader;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.io.InputStream;
import java.io.InputStreamReader;
import sun.misc.BASE64Decoder;
import java.security.spec.PKCS8EncodedKeySpec;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
public class RSAEncrypt {
private static final String DEFAULT_PUBLIC_KEY = ""
+ "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDDYMpmCWDPx6S36L"
+ "F7N53I/7SyuCwZoSQYEbXvQzo4uX3Q1vA9ADKqNlriSpcThoWKQ4JD"
+ "JUcFJn3rwS05TOPdNx3CIL4zT/x/XG369o9/Vzm"
+ "7dBBcPcPvEJxm+c+oOVydwGz5NvrROXOwVmYQfm"
+ "3Z/9LL6CfDzmR4wLFz16/OswIDAQAB";
private static final String DEFAULT_PRIVATE_KEY = ""
+ "MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAMNgymY"
+ "JYM/HpLfosXs3ncj/tLK4LBmhJBgRte9DOji5fdDW8D0AMqo2WuJKlx"
+ "OGhYpDgkMlRwUmfevBLTlM4903HcIgvjNP/H9cbfr2j39XObt0EFw9w"
+ "+8QnGb5z6g5XJ3AbPk2+tE5c7BWZhB+bdn/0svoJ8POZHjAsXPXr86z"
+ "AgMBAAECgYA0cSuCnevNecH910ikUTZZ+EDRY9v6eSVODJrwAPSEu01"
+ "JHBhZ107CH1rfuLO6evYnOZ2iVkQs3rsX578yzS+v/ZADdC7166KmDe"
+ "NkEoia01cfZN1dYdvowwMVRMImokBQth8iAS8tex7EPLNtDY6LJ6rEs"
+ "tT6an1+qfMeRn1+cQJBAPQz8d1Evo+JphCoijfFOS9d1NHihZxHD61I"
+ "/TuJDYC/494gOflCdYQLRfwfLOeFXDpb6Ej7OiQW49+jMqZ7fHsCQQD"
+ "M0Qea+ZfB4Y6leAUC40kF/sJLjJa2E22G+5FUVtM9HfiOlEmIW/s39V"
+ "NwiH8/XSMPYTMz7IBb79+LJzHuke0pAkAwVB9ntPUpnwo4fcJs6yE4G"
+ "I/HwdbDaOTXXHyRTbxYYKGOEj6m79ol+b0t+lV+tEveWNYNq3qELeuH"
+ "FNsvS30FAkAuT/m7RkLVeU5LBieD7qbdbyy57pFJnH0Ar7O98WAUisl"
+ "gXBGAfuQAVD3IzWSQjFvYJ29vh0PDBitzCKrWujJ5AkEA0h+tTr4CzV"
+ "KE+nwEM+asWLAnp6bnO7NoOBv2SWkAtRXdtzz2WE+ZIGmy+AZJ/wHx4"
+ "RCfg8P0rXov+KLVyJX+MQ==";
/**
* 私钥
*/
private RSAPrivateKey privateKey;
/**
* 公钥
*/
private RSAPublicKey publicKey;
/**
* 字节数据转字符串专用集合
*/
private static final char[] HEX_CHAR = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e',
'f' };
/**
* 获得私钥
*
* @return 当前私钥对象
*/
public RSAPrivateKey getPrivateKey() {
return this.privateKey;
}
/**
* 获取公钥
*
* @return 当前公钥对象
*/
public RSAPublicKey getPublicKey() {
return publicKey;
}
/**
* 随机生成密钥对
*/
public void genKeyPair() {
KeyPairGenerator keyPairGen = null;
try {
keyPairGen = KeyPairGenerator.getInstance("RSA");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
keyPairGen.initialize(1024, new SecureRandom());
KeyPair keyPair = keyPairGen.generateKeyPair();
this.privateKey = (RSAPrivateKey) keyPair.getPrivate();
this.publicKey = (RSAPublicKey) keyPair.getPublic();
}
public void loadPublicKey(InputStream in) throws Exception {
try {
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String readLine = null;
StringBuilder sb = new StringBuilder();
while ((readLine = br.readLine()) != null) {
if (readLine.charAt(0) == '-') {
continue;
} else {
sb.append(readLine);
sb.append('\r');
}
}
loadPublicKey(sb.toString());
} 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");
}
}
/**
* 从字符串中加载公钥
*
* @param publicKeyStr
* 公钥数据字符串
* @throws Exception
* 加载公钥时产生的异常
*/
public void loadPublicKey(String publicKeyStr) throws Exception {
try {
BASE64Decoder base64Decoder = new BASE64Decoder();
byte[] buffer = base64Decoder.decodeBuffer(publicKeyStr);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
this.publicKey = (RSAPublicKey) keyFactory.generatePublic(keySpec);
} catch (NoSuchAlgorithmException e) {
throw new Exception("无此算法");
} catch (InvalidKeySpecException e) {
throw new Exception("公钥非法");
} catch (IOException e) {
throw new Exception("公钥数据内容读取错误");
} catch (NullPointerException e) {
throw new Exception("公钥数据为空");
}
}
/**
* 从文件中加载私钥
* @param keyFileName 私钥文件名
* @return 是否成功
* @throws Exception
*/
public void loadPrivateKey(InputStream in)throws Exception{
try{
BufferedReader br=new BufferedReader(new InputStreamReader(in));
String readLine=null;
StringBuilder sb =new StringBuilder();
while((readLine=br.readLine())!=null){
if((readLine.charAt(0)=='-')){
continue;
}else{
sb.append(readLine);
sb.append('\r');
}
}
loadPrivateKey(sb.toString());
}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");
}
}
/**
* 从字符串中加载私钥
*/
public void loadPrivateKey(String privateKeyStr) throws Exception{
try{
BASE64Decoder base64Decoder=new BASE64Decoder();
byte[] buffer=base64Decoder.decodeBuffer(privateKeyStr);
PKCS8EncodedKeySpec keySpec=new PKCS8EncodedKeySpec(buffer);
KeyFactory keyFactory=KeyFactory.getInstance("RSA");
this.privateKey=(RSAPrivateKey)keyFactory.generatePrivate(keySpec);
}catch(NoSuchAlgorithmException e){
throw new Exception("无此算法");
}catch(InvalidKeySpecException e){
throw new Exception("私钥非法");
}catch(IOException e){
throw new Exception("私钥数据内容读取错误");
}catch(NullPointerException e){
throw new Exception("私钥数据为空");
}
}
/**
* 加密过程
* @param publicKey 公钥
* @param plainTextData 明文数据
* @return
* @throws Exception 加密过程中的异常信息
*/
public byte[] encrypt(RSAPublicKey publicKey,byte[] plainTextDate) throws Exception{
if(publicKey==null){
throw new Exception("加密公钥为为空，请设置");
}
Cipher cipher=null;
try{
cipher= Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] output= cipher.doFinal(plainTextDate);
return output;
}catch (NoSuchAlgorithmException e) {
throw new Exception("无此加密算法");
} catch (NoSuchPaddingException e) {
e.printStackTrace();
return null;
}catch (InvalidKeyException e) {
throw new Exception("加密公钥非法,请检查");
} catch (IllegalBlockSizeException e) {
throw new Exception("明文长度非法");
} catch (BadPaddingException e) {
throw new Exception("明文数据已损坏");
}
}
/**
* 解密过程
* @param privateKey 私钥
* @param cipherData 密文数据
* @return 明文
* @throws Exception 解密过程中的异常信息
*/
public byte[] decrypt(RSAPrivateKey privateKey,byte[] cipherData)throws Exception{
if(privateKey==null){
throw new Exception("解密私钥为空，请设置");
}
Cipher cipher=null;
try{
cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] output=cipher.doFinal(cipherData);
return output;
}catch (NoSuchAlgorithmException e) {
throw new Exception("无此解密算法");
} catch (NoSuchPaddingException e) {
e.printStackTrace();
return null;
}catch (InvalidKeyException e) {
throw new Exception("解密私钥非法,请检查");
} catch (IllegalBlockSizeException e) {
throw new Exception("密文长度非法");
} catch (BadPaddingException e) {
throw new Exception("密文数据已损坏");
}
}
/**
* 字节数据转十六位进制字符串
* @param data 输入数据
* @return 十六进制内容
*/
public static String buteArrayToString(byte[] data){
StringBuilder stringBuilder=new StringBuilder();
for (int i = 0; i < data.length; i++) {
//取出字节的高四位，作为索引得到相应的十六位进制标识符，注意无符号右移
stringBuilder.append(HEX_CHAR[(data[i] & 0xf0)>>> 4]);
//取出字节的低四位，作为索引得到相应的十六进制标识符
stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);
if (i<data.length-1){
stringBuilder.append(' ');
}
}
return stringBuilder.toString();
}
public static void main(String[] args){
RSAEncrypt rsaEncrypt=new RSAEncrypt();
//rsaEncrypt.getKeyPair();
//加载公钥
try{
rsaEncrypt.loadPublicKey(RSAEncrypt.DEFAULT_PUBLIC_KEY);
System.out.println("加载公钥成功");
}catch(Exception e){
System.err.println(e.getMessage());
System.err.println("加载公钥失败");
}
//加载私钥
try{
rsaEncrypt.loadPrivateKey(RSAEncrypt.DEFAULT_PRIVATE_KEY);
System.out.println("加载私钥成功");
}catch(Exception e){
System.err.println(e.getMessage());
System.err.println("加载私钥失败");
}
//测试字符串
String encryptStr="这是Koow的RSA加密解密测试!";
try{
//加密
byte[] cipher=rsaEncrypt.encrypt(rsaEncrypt.getPublicKey(), encryptStr.getBytes());
//解密
byte[] plainText=rsaEncrypt.decrypt(rsaEncrypt.getPrivateKey(), cipher);
System.out.println("密文长度:"+cipher.length);
System.out.println(RSAEncrypt.buteArrayToString(cipher));
System.out.println("明文长度:"+plainText.length);
System.out.println(RSAEncrypt.buteArrayToString(plainText));
System.out.println(new String(plainText));
}catch (Exception e) {
System.err.println(e.getMessage());
}
}
}
结果如下：
