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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;
}@endpackage 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