IOS、java支持DES加密

最近在考虑数据加密方面的需求，所以对数据加密简单的看了一下，当然不是看的原理，只是看看怎么能够实现。现在我们需要实现的是移动端和后台（java）数据加解密的配合，开始的时候考虑的使用RSA，因为RSA是非对称加密，更加安全点，但是RSA加密的过程中，ios公钥加密的数据，后台java是能够解密成功，但是后台java私钥加密的东西，前端ios，就没有解密成功，实验了很多方法，最终也没有成功，所以就放弃了，转向了安全性差一点的DES加密。

对于DES、RSA的介绍，自己百度去吧，因为我也说不明白。（上面我没有提Android，因为Android使用的是java，所以应该跟后台一致）

下面废话不多说，直接贴上代码：

IOS，需要引入GTMBase64.h、GTMBase64.m、GTMDefines.h，这个github上面有我，自己搜搜吧，还有<CommonCrypto/CommonCryptor.h>。

[objc] view plaincopy
#import "ViewController.h"  
#import <CommonCrypto/CommonCryptor.h>  
#import "GTMBase64.h"  
  
@interface ViewController ()  
  
@end  
  
@implementation ViewController  
  
-(void)viewDidLoad {  
    [super viewDidLoad];  
      
    NSString *key = @"这是个key";  
    NSString *encryptedData = [self encryptUseDES:@"this is a text" key:key];  
    NSLog(@"加密后的数据是:%@", encryptedData);  
    NSLog(@"解密后的数据是:%@", [self decryptUseDES:encryptedData key:key]);  
}  
  
-(void)didReceiveMemoryWarning {  
    [super didReceiveMemoryWarning];  
    // Dispose of any resources that can be recreated.  
}  
 
/*字符串加密 
 *参数 
 *plainText : 加密明文 
 *key        : 密钥 64位 
 */  
-(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key  
{  
    NSString *ciphertext = nil;  
    const charchar *textBytes = [plainText UTF8String];  
    NSUInteger dataLength = [plainText length];  
    unsigned char buffer[1024];  
    memset(buffer, 0, sizeof(char));  
    Byte iv[] = {1,2,3,4,5,6,7,8};  
    size_t numBytesEncrypted = 0;  
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,  
                                          kCCOptionPKCS7Padding,  
                                          [key UTF8String], kCCKeySizeDES,  
                                          iv,  
                                          textBytes, dataLength,  
                                          buffer, 1024,  
                                          &numBytesEncrypted);  
    if (cryptStatus == kCCSuccess) {  
        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];  
          
        ciphertext = [[NSString alloc] initWithData:[GTMBase64 encodeData:data] encoding:NSUTF8StringEncoding];  
    }  
    return ciphertext;  
}  
  
//解密  
-(NSString *) decryptUseDES:(NSString*)cipherText key:(NSString*)key  
{  
    NSData* cipherData = [GTMBase64 decodeString:cipherText];  
    unsigned char buffer[1024];  
    memset(buffer, 0, sizeof(char));  
    size_t numBytesDecrypted = 0;  
    Byte iv[] = {1,2,3,4,5,6,7,8};  
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,  
                                          kCCAlgorithmDES,  
                                          kCCOptionPKCS7Padding,  
                                          [key UTF8String],  
                                          kCCKeySizeDES,  
                                          iv,  
                                          [cipherData bytes],  
                                          [cipherData length],  
                                          buffer,  
                                          1024,  
                                          &numBytesDecrypted);  
    NSString* plainText = nil;  
    if (cryptStatus == kCCSuccess) {  
        NSData* data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesDecrypted];  
        plainText = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];  
    }  
    return plainText;  
}  
  
  
@end 

java 代码：需要自己引入sun.misc.BASE64Decoder.jar

[java] view plaincopy
package com.yue;  
  
import java.io.IOException;  
import java.security.SecureRandom;  
  
import javax.crypto.Cipher;  
import javax.crypto.SecretKey;  
import javax.crypto.SecretKeyFactory;  
import javax.crypto.spec.DESKeySpec;  
  
import Decoder.BASE64Decoder;  
import Decoder.BASE64Encoder;  
   
   
public class DesUtil {  
   
    private final static String DES = "DES";  
   
    public static void main(String[] args) throws Exception {  
        String data = "123 456";  
        String key = "abcdefgh";  
        System.err.println(encrypt(data, key));  
        System.err.println(decrypt(encrypt(data, key), key));  
          
        System.out.println(decrypt("JF5dX/TlOg529KAhh+vywjzIp5Msktmf", key));  
   
    }  
       
    /** 
     * Description 根据键值进行加密 
     * @param data  
     * @param key  加密键byte数组 
     * @return 
     * @throws Exception 
     */  
    public static String encrypt(String data, String key) throws Exception {  
        byte[] bt = encrypt(data.getBytes(), key.getBytes());  
        String strs = new BASE64Encoder().encode(bt);  
        return strs;  
    }  
   
    /** 
     * Description 根据键值进行解密 
     * @param data 
     * @param key  加密键byte数组 
     * @return 
     * @throws IOException 
     * @throws Exception 
     */  
    public static String decrypt(String data, String key) throws IOException,  
            Exception {  
        if (data == null)  
            return null;  
        BASE64Decoder decoder = new BASE64Decoder();  
        byte[] buf = decoder.decodeBuffer(data);  
        byte[] bt = decrypt(buf,key.getBytes());  
        return new String(bt);  
    }  
   
    /** 
     * Description 根据键值进行加密 
     * @param data 
     * @param key  加密键byte数组 
     * @return 
     * @throws Exception 
     */  
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {  
        // 生成一个可信任的随机数源  
        SecureRandom sr = new SecureRandom();  
   
        // 从原始密钥数据创建DESKeySpec对象  
        DESKeySpec dks = new DESKeySpec(key);  
   
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象  
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);  
        SecretKey securekey = keyFactory.generateSecret(dks);  
   
        // Cipher对象实际完成加密操作  
        Cipher cipher = Cipher.getInstance(DES);  
   
        // 用密钥初始化Cipher对象  
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);  
   
        return cipher.doFinal(data);  
    }  
       
       
    /** 
     * Description 根据键值进行解密 
     * @param data 
     * @param key  加密键byte数组 
     * @return 
     * @throws Exception 
     */  
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {  
        // 生成一个可信任的随机数源  
        SecureRandom sr = new SecureRandom();  
   
        // 从原始密钥数据创建DESKeySpec对象  
        DESKeySpec dks = new DESKeySpec(key);  
   
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象  
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);  
        SecretKey securekey = keyFactory.generateSecret(dks);  
   
        // Cipher对象实际完成解密操作  
        Cipher cipher = Cipher.getInstance(DES);  
   
        // 用密钥初始化Cipher对象  
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);  
   
        return cipher.doFinal(data);  
    }  
}  

代码下载地址：http://download.csdn.net/detail/mengxiangyue/8028311