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;

}