RSA IOS和Java

整了三天 终于可以相互加密解密了，今天我给大家讲讲我遇到的大坑。

这篇文章只是做一个整理，帮大家理清一下步骤的而已

在ios端做证书 来实现我们和java的交流 需要4个文件。

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 3650 -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

在做这些证书时候注意填写你的信息，注意你的公钥格式是否正确。

代码中路径和头文件要注意

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。

这样你就可以和你之前查到了方法结合起来 ，来实现对话。

看看我们ios这边的操作
.h

#import <Foundation/Foundation.h>

@interface RSAEncryptor : NSObject

#pragma mark - Instance Methods

-(void) loadPublicKeyFromFile: (NSString*) derFilePath;
-(void) loadPublicKeyFromData: (NSData*) derData;

-(void) loadPrivateKeyFromFile: (NSString*) p12FilePath password:(NSString*)p12Password;
-(void) loadPrivateKeyFromData: (NSData*) p12Data password:(NSString*)p12Password;

-(NSString*) rsaEncryptString:(NSString*)string;
-(NSData*) rsaEncryptData:(NSData*)data ;

-(NSString*) rsaDecryptString:(NSString*)string;
-(NSData*) rsaDecryptData:(NSData*)data;

#pragma mark - Class Methods

+(void) setSharedInstance: (RSAEncryptor*)instance;
+(RSAEncryptor*) sharedInstance;

@end

.m

#import "RSAEncryptor.h"

#import <Security/Security.h>
#import "NSData+Base64.h"

@implementation RSAEncryptor
{
SecKeyRef publicKey;

SecKeyRef privateKey;
}

-(void)dealloc
{
CFRelease(publicKey);
CFRelease(privateKey);
}

-(SecKeyRef) getPublicKey {
return publicKey;
}

-(SecKeyRef) getPrivateKey {
return privateKey;
}

-(void) loadPublicKeyFromFile: (NSString*) derFilePath
{
NSData *derData = [[NSData alloc] initWithContentsOfFile:derFilePath];
[self loadPublicKeyFromData: derData];
}
-(void) loadPublicKeyFromData: (NSData*) derData
{
publicKey = [self getPublicKeyRefrenceFromeData: derData];
}

-(void) loadPrivateKeyFromFile: (NSString*) p12FilePath password:(NSString*)p12Password
{
NSData *p12Data = [NSData dataWithContentsOfFile:p12FilePath];
[self loadPrivateKeyFromData: p12Data password:p12Password];
}

-(void) loadPrivateKeyFromData: (NSData*) p12Data password:(NSString*)p12Password
{
privateKey = [self getPrivateKeyRefrenceFromData: p12Data password: p12Password];
}

#pragma mark - Private Methods

-(SecKeyRef) getPublicKeyRefrenceFromeData: (NSData*)derData
{
SecCertificateRef myCertificate = SecCertificateCreateWithData(kCFAllocatorDefault, (__bridge CFDataRef)derData);
SecPolicyRef myPolicy = SecPolicyCreateBasicX509();
SecTrustRef myTrust;
OSStatus status = SecTrustCreateWithCertificates(myCertificate,myPolicy,&myTrust);
SecTrustResultType trustResult;
if (status == noErr) {
status = SecTrustEvaluate(myTrust, &trustResult);
}
SecKeyRef securityKey = SecTrustCopyPublicKey(myTrust);
CFRelease(myCertificate);
CFRelease(myPolicy);
CFRelease(myTrust);

return securityKey;
}

-(SecKeyRef) getPrivateKeyRefrenceFromData: (NSData*)p12Data password:(NSString*)password
{
SecKeyRef privateKeyRef = NULL;
NSMutableDictionary * options = [[NSMutableDictionary alloc] init];
[options setObject: password forKey:(__bridge id)kSecImportExportPassphrase];
CFArrayRef items = CFArrayCreate(NULL, 0, 0, NULL);
OSStatus securityError = SecPKCS12Import((__bridge CFDataRef) p12Data, (__bridge CFDictionaryRef)options, &items);
if (securityError == noErr && CFArrayGetCount(items) > 0) {
CFDictionaryRef identityDict = CFArrayGetValueAtIndex(items, 0);
SecIdentityRef identityApp = (SecIdentityRef)CFDictionaryGetValue(identityDict, kSecImportItemIdentity);
securityError = SecIdentityCopyPrivateKey(identityApp, &privateKeyRef);
if (securityError != noErr) {
privateKeyRef = NULL;
}
}
CFRelease(items);

return privateKeyRef;
}

#pragma mark - Encrypt

-(NSString*) rsaEncryptString:(NSString*)string {
NSData* data = [string dataUsingEncoding:NSUTF8StringEncoding];
NSData* encryptedData = [self rsaEncryptData: data];
NSString* base64EncryptedString = [encryptedData base64EncodedString];
return base64EncryptedString;
}

// 加密的大小受限于SecKeyEncrypt函数，SecKeyEncrypt要求明文和密钥的长度一致，如果要加密更长的内容，需要把内容按密钥长度分成多份，然后多次调用SecKeyEncrypt来实现
-(NSData*) rsaEncryptData:(NSData*)data {
SecKeyRef key = [self getPublicKey];
size_t cipherBufferSize = SecKeyGetBlockSize(key);
uint8_t *cipherBuffer = malloc(cipherBufferSize * sizeof(uint8_t));
size_t blockSize = cipherBufferSize - 11; // 分段加密
size_t blockCount = (size_t)ceil([data length] / (double)blockSize);
NSMutableData *encryptedData = [[NSMutableData alloc] init] ;
for (int i=0; i<blockCount; i++) {
int bufferSize = MIN(blockSize,[data length] - i * blockSize);
NSData *buffer = [data subdataWithRange:NSMakeRange(i * blockSize, bufferSize)];
OSStatus status = SecKeyEncrypt(key, kSecPaddingPKCS1, (const uint8_t *)[buffer bytes], [buffer length], cipherBuffer, &cipherBufferSize);
if (status == noErr){
NSData *encryptedBytes = [[NSData alloc] initWithBytes:(const void *)cipherBuffer length:cipherBufferSize];
[encryptedData appendData:encryptedBytes];
}else{
if (cipherBuffer) {
free(cipherBuffer);
}
return nil;
}
}
if (cipherBuffer){
free(cipherBuffer);
}
return encryptedData;
}

#pragma mark - Decrypt

-(NSString*) rsaDecryptString:(NSString*)string {
NSData* data = [NSData dataFromBase64String: string];
NSData* decryptData = [self rsaDecryptData: data];
NSString* result = [[NSString alloc] initWithData: decryptData encoding:NSUTF8StringEncoding];
return result;
}

-(NSData*) rsaDecryptData:(NSData*)data {
SecKeyRef key = [self getPrivateKey];
size_t cipherLen = [data length];
void *cipher = malloc(cipherLen);
[data getBytes:cipher length:cipherLen];
size_t plainLen = SecKeyGetBlockSize(key) - 12;
void *plain = malloc(plainLen);
OSStatus status = SecKeyDecrypt(key, kSecPaddingPKCS1, cipher, cipherLen, plain, &plainLen);

if (status != noErr) {
return nil;
}

NSData *decryptedData = [[NSData alloc] initWithBytes:(const void *)plain length:plainLen];

return decryptedData;
}

#pragma mark - Class Methods

static RSAEncryptor* sharedInstance = nil;

+(void) setSharedInstance: (RSAEncryptor*)instance
{
sharedInstance = instance;
}

+(RSAEncryptor*) sharedInstance
{
return sharedInstance;
}

好了，那么，我们就可以在main.m里做个测试了:

#import "AppDelegate.h"
#import "RSAEncryptor.h"

int main(int argc, char *argv[])
{
@autoreleasepool {

RSAEncryptor* rsaEncryptor = [[RSAEncryptor alloc] init];
NSString* publicKeyPath = [[NSBundle mainBundle] pathForResource:@"public_key" ofType:@"der"];
NSString* privateKeyPath = [[NSBundle mainBundle] pathForResource:@"private_key" ofType:@"p12"];
[rsaEncryptor loadPublicKeyFromFile: publicKeyPath];
[rsaEncryptor loadPrivateKeyFromFile: privateKeyPath password:@"ISAACS"]; // 这里，请换成你生成p12时的密码

NSString* restrinBASE64STRING = [rsaEncryptor rsaEncryptString:@"I.O.S"];
NSLog(@"Encrypted: %@", restrinBASE64STRING); // 请把这段字符串Copy到JAVA这边main()里做测试
NSString* decryptString = [rsaEncryptor rsaDecryptString: restrinBASE64STRING];
NSLog(@"Decrypted: %@", decryptString);

// System.out.println the encrypt string from Java , and paste it here
// 这里请换成你的JAVA这边产生的加密的Base64 Encode的字符串
// NSString* rsaEncrypyBase64 = [NSString stringWithFormat:@"%@\r%@\r%@",
// @"ZNKCVpFYd4Oi2pecLhDXHh+8kWltUMLdBIBDeTvU5kWpTQ8cA1Y+7wKO3d/M8bhULYf1FhWt80Cg",
// @"7e73SV5r+wSlgGWBvTIxqgTWFS4ELGzsEJpVVSlK1oXF0N2mugOURUILjeQrwn1QTcVdXXTMQ0wj",
// @"50GNwnHbAwyLvsY5EUY="];
//
// NSString* resultString = [rsaEncryptor rsaDecryptString: rsaEncrypyBase64];
// NSLog(@"Decrypt Java RSA String: %@", resultString);

return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
}
}

代码里注意请把密码修改换成你的p12密码。

　　在main.m的main()函数里有几行注释了的代码，因为那个 ‘rsaEncrypyBase64’ 是我在JAVA端用我的公钥私钥生成的，不适合你的公钥私钥，所以我注释掉。待会做完下面JAVA的，你用你在JAVA端生成的加密字符串替换‘rsaEncrypyBase64’的值，打开注释来测试 JAVA端加密的数据能不能被IOS这端来 解密。(答案是能的)

三、 JAVA 代码

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/Isaacs/Desktop/RSA_KEYS/rsa_public_key.pem"; // replace your public key path here
String publicKeyPath = "/Users/Isaacs/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();
}

｝

同样的，main()函数里有几行注释了的代码，打开注释， 请复制上面IOS端的加密字符串来替换掉，这样，来测试一下来自IOS端的加密数据能不能被JAVA端解密。(答案也是能的)