IOS & JAVA RSA Encryption & Decryption
在网上找了许多篇关于RSA加密解密的文章与博客，是很有帮助，但比较零散与不简洁。
(至于RSA的基本原理，大家可以看 阮一峰的网络日志 的 RSA算法原理（一） 和 RSA算法原理（二） )
这篇文章只是做一个整理，帮大家理清一下步骤的而已（ 英文版本请看 RSA Encrypt and Decrypt in IOS and JAVA ）。
一、首先，打开Terminal， 生成必要的公钥、私钥、证书:
openssl genrsa -out private_key.pem 1024 openssl req -new -key private_key.pem -out rsaCertReq.csr openssl x509 -req -days 36500 -in rsaCertReq.csr -signkey private_key.pem -out rsaCert.crt openssl x509 -outform der -in rsaCert.crt -out public_key.der // Create public_key.der For IOS openssl pkcs12 -export -out private_key.p12 -inkey private_key.pem -in rsaCert.crt // Create private_key.p12 For IOS. 这一步，请记住你输入的密码，IOS代码里会用到 openssl rsa -in private_key.pem -out rsa_public_key.pem -pubout // Create rsa_public_key.pem For Java openssl pkcs8 -topk8 -in private_key.pem -out pkcs8_private_key.pem -nocrypt // Create pkcs8_private_key.pem For Java
上面七个步骤，总共生成7个文件。其中 public_key.der 和 private_key.p12 这对公钥私钥是给IOS用的， rsa_public_key.pem 和 pkcs8_private_key.pem 是给JAVA用的。
它们的源都来自一个私钥：private_key.pem ， 所以IOS端加密的数据，是可以被JAVA端解密的，反过来也一样。
二、IOS 端:
2017.0306更新，文章过时了啦，大家请参考一个大神的Github: Objective-C-RSA
三、 JAVA 端：
RSAEncryptor.java：
package com.modules.Encryptor;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.ArrayList;
import java.util.List;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
public class RSAEncryptor {
public static void main(String[] args){
String privateKeyPath = "/Users/Love/Desktop/RSA_KEYS/rsa_public_key.pem"; // replace your public key path here
String publicKeyPath = "/Users/Love/Desktop/RSA_KEYS/pkcs8_private_key.pem"; // replace your private path here
RSAEncryptor rsaEncryptor = new RSAEncryptor(privateKeyPath, publicKeyPath);
try {
String test = "JAVA";
String testRSAEnWith64 = rsaEncryptor.encryptWithBase64(test);
String testRSADeWith64 = rsaEncryptor.decryptWithBase64(testRSAEnWith64);
System.out.println("\nEncrypt: \n" + testRSAEnWith64);
System.out.println("\nDecrypt: \n" + testRSADeWith64);
// NSLog the encrypt string from Xcode , and paste it here.
// 请粘贴来自IOS端加密后的字符串
// String rsaBase46StringFromIOS =
// "nIIV7fVsHe8QquUbciMYbbumoMtbBuLsCr2yMB/WAhm+S/kGRPlf+k2GH8imZIYQ" + "\r" +
// "QBDssVLQmS392QlxS87hnwMRJIzWw6vdRv/k79TgTfu6tI/9QTqIOvNlQIqtIcVm" + "\r" +
// "R/suvydoymKgdlB+ce5/tHSxfqEOLLrL1Zl2PqJSP4A=";
//
// String decryptStringFromIOS = rsaEncryptor.decryptWithBase64(rsaBase46StringFromIOS);
// System.out.println("Decrypt result from ios client: \n" + decryptStringFromIOS);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* @param publicKeyFilePath
* @param privateKeyFilePath
*/
public RSAEncryptor(String publicKeyFilePath, String privateKeyFilePath) throws Exception {
String public_key = getKeyFromFile(publicKeyFilePath);
String private_key = getKeyFromFile(privateKeyFilePath);
loadPublicKey(public_key);
loadPrivateKey(private_key);
}
public RSAEncryptor() {
// load the PublicKey and PrivateKey manually
}
public String getKeyFromFile(String filePath) throws Exception {
BufferedReader bufferedReader = new BufferedReader(new FileReader(filePath));
String line = null;
List<String> list = new ArrayList<String>();
while ((line = bufferedReader.readLine()) != null){
list.add(line);
}
// remove the firt line and last line
StringBuilder stringBuilder = new StringBuilder();
for (int i = 1; i < list.size() - 1; i++) {
stringBuilder.append(list.get(i)).append("\r");
}
String key = stringBuilder.toString();
return key;
}
public String decryptWithBase64(String base64String) throws Exception {
// http://commons.apache.org/proper/commons-codec/ : org.apache.commons.codec.binary.Base64
// sun.misc.BASE64Decoder
byte[] binaryData = decrypt(getPrivateKey(), new BASE64Decoder().decodeBuffer(base64String) /*org.apache.commons.codec.binary.Base64.decodeBase64(base46String.getBytes())*/);
String string = new String(binaryData);
return string;
}
public String encryptWithBase64(String string) throws Exception {
// http://commons.apache.org/proper/commons-codec/ : org.apache.commons.codec.binary.Base64
// sun.misc.BASE64Encoder
byte[] binaryData = encrypt(getPublicKey(), string.getBytes());
String base64String = new BASE64Encoder().encodeBuffer(binaryData) /* org.apache.commons.codec.binary.Base64.encodeBase64(binaryData) */;
return base64String;
}
// convenient properties
public static RSAEncryptor sharedInstance = null;
public static void setSharedInstance (RSAEncryptor rsaEncryptor) {
sharedInstance = rsaEncryptor;
}
// From: http://blog.csdn.net/chaijunkun/article/details/7275632
/**
* 私钥
*/
private RSAPrivateKey privateKey;
/**
* 公钥
*/
private RSAPublicKey publicKey;
/**
* 获取私钥
* @return 当前的私钥对象
*/
public RSAPrivateKey getPrivateKey() {
return privateKey;
}
/**
* 获取公钥
* @return 当前的公钥对象
*/
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();
}
/**
* 从文件中输入流中加载公钥
* @param in 公钥输入流
* @throws Exception 加载公钥时产生的异常
*/
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");
}
}
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) {
e.printStackTrace();
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[] plainTextData) throws Exception{
if(publicKey== null){
throw new Exception("加密公钥为空, 请设置");
}
Cipher cipher= null;
try {
cipher= Cipher.getInstance("RSA");//, new BouncyCastleProvider());
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] output= cipher.doFinal(plainTextData);
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");//, new BouncyCastleProvider());
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'};
/**
* 字节数据转十六进制字符串
* @param data 输入数据
* @return 十六进制内容
*/
public static String byteArrayToString(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();
}
｝
