Objective-C中的AES字符串加密 [英] AES string encryption in Objective-C

问题描述

我的Objective-C应用程式需要文字/字串加密（特别是 nsstring ）。

My Objective-C App requires text / string encryption (specifically nsstring).

我知道AES是可供消费者使用的最安全的加密方法。我也理解如何将字符串转换为数据和回...（只是一个初学者）。

I know AES is the most secure encryption method available for consumer use. I also understand how to convert strings to data and back... (just a beginner).

许多网页和关于使用AES进行加密的问题不清楚，并且都没有说明如何使用给定的代码。例如，网页可能会说：这里是代码...这里是它的作用...但没有解释如何使用它。

Many webpages and Q/As about encryption with AES are unclear, and none of them state how to use the code given. For example, a webpage might say: "here is the code... here is what it does..." but no explanation for how to use it.

我通过大量研究发现了这个代码：

I've found this code through lots of research:

#import "<CommonCrypto/CommonCryptor.h>"
@implementation NSMutableData(AES)

加密：

- (NSMutableData*) EncryptAES:(NSString *)key {
    char keyPtr[kCCKeySizeAES256+1];
    bzero( keyPtr, sizeof(keyPtr) );

    [key getCString: keyPtr maxLength: sizeof(keyPtr) encoding: NSUTF16StringEncoding];
    size_t numBytesEncrypted = 0;

    NSUInteger dataLength = [self length];

    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);

    NSMutableData *output = [[NSData alloc] init];

    CCCryptorStatus result = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES256, NULL, [self mutableBytes], [self length], buffer, bufferSize, &numBytesEncrypted);

    output = [NSMutableData dataWithBytesNoCopy:buffer length:numBytesEncrypted];

    if(result == kCCSuccess) {
        return output;
    }
        return NULL;
    }

对于解密：

- (NSMutableData*)DecryptAES: (NSString*)key andForData:(NSMutableData*)objEncryptedData {

    char  keyPtr[kCCKeySizeAES256+1];
    bzero( keyPtr, sizeof(keyPtr) );

    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF16StringEncoding];

    size_t numBytesEncrypted = 0;

    NSUInteger dataLength = [self length];

    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer_decrypt = malloc(bufferSize);    
    NSMutableData *output_decrypt = [[NSData alloc] init];
    CCCryptorStatus result = CCCrypt(kCCDecrypt , kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES256, NULL, [self mutableBytes], [self length], buffer_decrypt, bufferSize, &numBytesEncrypted);

    output_decrypt = [NSMutableData dataWithBytesNoCopy:buffer_decrypt length:numBytesEncrypted];

    if(result == kCCSuccess) {
        return output_decrypt;
    } 
        return NULL;
    }
}

这是我要的代码对应于上述代码：

This is the code I made that I would like to correspond with the above code:

- (void)Encrypt {
    //Convert NSString to NSData so that it can be used to encrypt the Input
    NSString *Input  = [Inputbox text];
    NSData *InputData = [Input dataUsingEncoding:NSUTF8StringEncoding];
    //What to do here
}

，这些方法？

推荐答案

靠近顶部的这一行表示您正在向NSMutableData添加AES功能：

This line near the top says you're adding AES functionality to NSMutableData:

@implementation NSMutableData(AES)

在Objective-C中，这被称为类别;类别允许您扩展现有类。

In Objective-C, this is called a category; categories let you extend an existing class.

此代码通常位于名为NSMutableData-AES.m的文件中。也创建一个头文件，NSMutableData-AES.h。它应该包含：

This code would typically go in a file named NSMutableData-AES.m. Create a header file too, NSMutableData-AES.h. It should contain:

@interface NSMutableData(AES)
- (NSMutableData*) EncryptAES: (NSString *) key;
@end

在主文件中包含（#import）在代码中添加对加密函数的调用：

Include (#import) that header in your main file. Add a call to the encryption function in your code:

NSData *InputData = [Input dataUsingEncoding:NSUTF8StringEncoding];
NSData *encryptedData = [InputData EncryptAES:@"myencryptionkey"];

类似地解密。

这篇关于Objective-C中的AES字符串加密的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！