objective-c - iOS 13 中的 AES 加密 CryptLib 不起作用

Question

我的应用程序使用 AES 256 加密来加密字符串。之前使用的相同代码会生成不同的结果。这个问题在 iOS 13 发布时就开始出现。这种情况仅发生在发布到商店或使用 Xcode 11 构建的应用程序中。

这是用于加密的代码:

<小时/>

- (NSData *)encrypt:(NSData *)plainText key:(NSString *)key  iv:(NSString *)iv {  
    char keyPointer[kCCKeySizeAES256+2],// room for terminator (unused) ref: https://devforums.apple.com/message/876053#876053  
    ivPointer[kCCBlockSizeAES128+2];  
    BOOL patchNeeded;  
    bzero(keyPointer, sizeof(keyPointer)); // fill with zeroes for padding  

    patchNeeded= ([key length] > kCCKeySizeAES256+1);  
    if(patchNeeded)  
    {  
        NSLog(@"Key length is longer %lu", (unsigned long)[[self md5:key] length]);  
        key = [key substringToIndex:kCCKeySizeAES256]; // Ensure that the key isn't longer than what's needed (kCCKeySizeAES256)  
    }  

    //NSLog(@"md5 :%@", key);  
    [key getCString:keyPointer maxLength:sizeof(keyPointer) encoding:NSUTF8StringEncoding];  
    [iv getCString:ivPointer maxLength:sizeof(ivPointer) encoding:NSUTF8StringEncoding];  

    if (patchNeeded) {  
        keyPointer[0] = '\0';  // Previous iOS version than iOS7 set the first char to '\0' if the key was longer than kCCKeySizeAES256  
    }  

    NSUInteger dataLength = [plainText length];  

    //see https://developer.apple.com/library/ios/documentation/System/Conceptual/ManPages_iPhoneOS/man3/CCryptorCreateFromData.3cc.html  
    // For block ciphers, the output size will always be less than or equal to the input size plus the size of one block.  
    size_t buffSize = dataLength + kCCBlockSizeAES128;  
    void *buff = malloc(buffSize);  

    size_t numBytesEncrypted = 0;  
    //refer to http://www.opensource.apple.com/source/CommonCrypto/CommonCrypto-36064/CommonCrypto/CommonCryptor.h  
    //for details on this function  
    //Stateless, one-shot encrypt or decrypt operation.  
    CCCryptorStatus status = CCCrypt(kCCEncrypt, /* kCCEncrypt, etc. */  
                                     kCCAlgorithmAES128, /* kCCAlgorithmAES128, etc. */  
                                     kCCOptionPKCS7Padding, /* kCCOptionPKCS7Padding, etc. */  
                                     keyPointer, kCCKeySizeAES256, /* key and its length */  
                                     ivPointer, /* initialization vector - use random IV everytime */  
                                     [plainText bytes], [plainText length], /* input  */  
                                     buff, buffSize,/* data RETURNED here */  
                                     &numBytesEncrypted);  
    if (status == kCCSuccess) {  
        return [NSData dataWithBytesNoCopy:buff length:numBytesEncrypted];  
    }  

    free(buff);  
    return nil;  
}  


- (NSString *) encryptPlainTextWith:(NSString *)plainText key:(NSString *)key iv:(NSString *)iv {  
    return [[[[CryptLib alloc] init] encrypt:[plainText dataUsingEncoding:NSUTF8StringEncoding] key:[[CryptLib alloc] sha256:key length:32] iv:iv] base64EncodedStringWithOptions:0];  
} 
/** 

* This function computes the SHA256 hash of input string 
* @param key input text whose SHA256 hash has to be computed 
* @param length length of the text to be returned 
* @return returns SHA256 hash of input text 
*/  
- (NSString*) sha256:(NSString *)key length:(NSInteger) length{  
    const char *s=[key cStringUsingEncoding:NSASCIIStringEncoding];  
    NSData *keyData=[NSData dataWithBytes:s length:strlen(s)];  

    uint8_t digest[CC_SHA256_DIGEST_LENGTH]={0};  
    CC_SHA256(keyData.bytes, (CC_LONG)keyData.length, digest);  
    NSData *out=[NSData dataWithBytes:digest length:CC_SHA256_DIGEST_LENGTH];  
    NSString *hash=[out description];  
    hash = [hash stringByReplacingOccurrencesOfString:@" " withString:@""];  
    hash = [hash stringByReplacingOccurrencesOfString:@"<" withString:@""];  
    hash = [hash stringByReplacingOccurrencesOfString:@">" withString:@""];  

    if(length > [hash length])  
    {  
        return  hash;  
    }  
    else  
    {  
        return [hash substringToIndex:length];  
    }  
}

##

我想知道代码路径中的某些内容的工作方式是否发生了变化。进行加密所调用的方法是“encryptPlainTextWith”。提前致谢。

Answer 1

内部:

- (NSString*) sha256:(NSString *)key length:(NSInteger) length

我替换了

NSString *hash=[out description];

至

NSString *hash=[out debugDescription];

一切都恢复正常了。干杯快乐编码。

@Rob Napier 的替代解决方案

创建单独的函数将 NSData 转换为十六进制

#pragma mark - String Conversion
-(NSString*)hex:(NSData*)data{
     NSMutableData *result = [NSMutableData dataWithLength:2*data.length];
     unsigned const char* src = data.bytes;
     unsigned char* dst = result.mutableBytes;
     unsigned char t0, t1;

     for (int i = 0; i < data.length; i ++ ) {
          t0 = src[i] >> 4;
          t1 = src[i] & 0x0F;

          dst[i*2] = 48 + t0 + (t0 / 10) * 39;
          dst[i*2+1] = 48 + t1 + (t1 / 10) * 39;
     }

     return [[NSString alloc] initWithData:result encoding:NSASCIIStringEncoding];
}

之后里面:

- (NSString*) sha256:(NSString *)key length:(NSInteger) length

我替换了

NSString *hash=[out description];

至

NSString *hash = [self hex:out];