iphone程序加密处理

在Objective-C语言中，加密时常用到CCCrypt(3cc)面的代码使用 CCCrypt() ，给 NSData 类增加了AES256EncryptWithKey, AES256DecryptWithKey 方法

- (NSData *)AES256EncryptWithKey:(NSString *)key 

{


        char keyPtr[kCCKeySizeAES256+1];
        

bzero(keyPtr, sizeof(keyPtr));


        [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];


        NSUInteger dataLength = [self length];


        size_t bufferSize = dataLength + kCCBlockSizeAES128;

 void *buffer = malloc(bufferSize);

        

size_t numBytesEncrypted = 0;

 CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,
                                                                         kCCOptionPKCS7Padding | kCCOptionECBMode,
                                                                         keyPtr, kCCBlockSizeAES128,
                                                                         NULL,
                                                                         [self bytes], dataLength,
                                                                         buffer, bufferSize,
                                                                         &numBytesEncrypted);


if (cryptStatus == kCCSuccess) 

{
                return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
        }

 free(buffer);
        return nil;


}



 - (NSData *)AES256DecryptWithKey:(NSString *)key

{
        

char keyPtr[kCCKeySizeAES256+1];

 bzero(keyPtr, sizeof(keyPtr));

        

[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

        

NSUInteger dataLength = [self length];

        

size_t bufferSize = dataLength + kCCBlockSizeAES128;
        

void *buffer = malloc(bufferSize);


        size_t numBytesDecrypted = 0;

CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128,
                                                                         kCCOptionPKCS7Padding | kCCOptionECBMode,
                                                                         keyPtr, kCCBlockSizeAES128,
                                                                         NULL,
                                                                         [self bytes], dataLength,
                                                                         buffer, bufferSize,
                                                                         &numBytesDecrypted);

        

if (cryptStatus == kCCSuccess)

 {
                return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
        }


        free(buffer);
        return nil;


}