IOS、java支持DES加密

转载请注明博客地址：http://blog.csdn.net/mengxiangyue/article/details/40015727

近期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，仅仅是看看怎么可以实现。如今我们须要实现的是移动端和后台（java）数据加解密的配合，開始的时候考虑的使用RSA，由于RSA是非对称加密，更加安全点，可是RSA加密的过程中，ios公钥加密的数据，后台java是可以解密成功，可是后台java私钥加密的东西，前端ios，就没有解密成功，实验了非常多方法，终于也没有成功，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，由于我也说不明确。（上面我没有提Android，由于Android使用的是java，所以应该跟后台一致）

以下废话不多说，直接贴上代码：

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

#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
 *參数
 *plainText : 加密明文
 *key        : 密钥 64位
 */
- (NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key
{
    NSString *ciphertext = nil;
    const char *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：须要自己引入sun.misc.BASE64Decoder.jar

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 依据键值进行加密
     * @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 依据键值进行解密
     * @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 依据键值进行加密
     * @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对象实际完毕加密操作
        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 依据键值进行解密
     * @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对象实际完毕解密操作
        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