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);
}
} 