我有一个函数需要我将加密的 JSON 实例发送到 PHP 服务器进行验证。我在尝试启动和运行整个过程时遇到了问题，我绞尽脑汁想找出问题所在。

-(void) sendData:(NSString*)theweb{  
        //preparing sample json        
        NSMutableDictionary * dict = [[NSMutableDictionary alloc]init];
        [dict setObject:@"test" forKey:@"example"];
        [dict setObject:@"1" forKey:@"p"];
        [dict setObject:@"yourPostMessage" forKey:@"test"];
        [dict setObject:@"isNotReal" forKey:@"this"];

        //json creation
        NSData* data2 = [JSONBuilder toJSON:dict];

        NSString * jsonstring = [[NSString alloc]initWithData:data2 encoding:NSUTF8StringEncoding];

        //creating a dummy sha256 hash for aes256 key.
        NSString * string3 = [self sha256HashFor:@"hello"];

        //trimming hash to 32 character key.
        string3 = [string3 substringToIndex:32];

        //encrypting data to aes256
        data2 = [data2 AES256EncryptWithKey:string3];

        NSString * b64= [data2 base64EncodedString];

        NSString *post = [NSString stringWithFormat:@"theRealData=%@",b64];
        NSData *postData = [post dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];

        requestObj = nil;

        //NSMutableRequest
        requestObj = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:theweb]];

        NSString *postLength =  [NSString stringWithFormat:@"%d", [postData length]];

        [requestObj setValue:@"application/x-www-form-urlencoded;charset=charset=us-ascii" forHTTPHeaderField:@"Content-Type"];

        [requestObj setValue:postLength forHTTPHeaderField:@"Content-Length"];

        [requestObj setHTTPMethod:@"POST"];
        [requestObj setHTTPBody:postData];

        //calling a new NSURLConnection
        conn = nil;
        conn = [NSURLConnection connectionWithRequest:requestObj delegate:self];

        [conn start];        

}

该函数使用的方法如下:

+(NSData*)toJSON :(NSMutableDictionary*)dictionary
{
    NSError* error = nil;
    id result = [NSJSONSerialization dataWithJSONObject:dictionary options:kNilOptions error:&error];
    if (error != nil) return nil;
    return result;
}

-(NSString*)sha256HashFor:(NSString*)input
{
    const char* str = [input UTF8String];
    unsigned char result[CC_SHA256_DIGEST_LENGTH];
    CC_SHA256(str, strlen(str), result);

    NSMutableString *ret = [NSMutableString stringWithCapacity:CC_SHA256_DIGEST_LENGTH*2];
    for(int i = 0; i<CC_SHA256_DIGEST_LENGTH; i++)
    {
        [ret appendFormat:@"%02x",result[i]];
    }
    return ret;
}

- (NSData *)AES256EncryptWithKey:(NSString *)key {
    // 'key' should be 32 bytes for AES256, will be null-padded otherwise
    char keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)
    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)

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

    NSUInteger dataLength = [self length];

    //See the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That's why we need to add the size of one block here
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);

    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                      keyPtr, kCCKeySizeAES256,
                                      NULL /* initialization vector (optional) */,
                                      [self bytes], dataLength, /* input */
                                      buffer, bufferSize, /* output */
                                      &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
    //the returned NSData takes ownership of the buffer and will free it on deallocation
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }

    free(buffer); //free the buffer;
    return nil;
    }

这是 php 上的代码:

function decrypt_data($data, $key) {
    //$padded_key = $key . str_repeat(chr(0x00), 16); // Argh!
    //var_dump($padded_key);

    var_dump(base64_decode($data,true));

    $result = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($data), 'ecb');


    var_dump($result);
    // Yetch - $result ends up being padded with 0x0b's (vertical tab).
    $result2 = rtrim($result, chr(0x0b));
    return $result2;
}

这是我的发现:

Output of Base64 string(Gotten on both sides):
    UalnWmRiMQv8z4mEm+6B3HFSbiDwWcK1LYPhk6jDq+DiwYzvxqoZuDnlJUAjWbX6sQepiL8fb8/JQ0NXhQocglIcJN759AbpVSsbiXmwL78=
Output of vardump on base64_decode on PHP side:
    BOOL(false)
Output of vardump on $result: none

不知何故，我觉得问题出在编码上。有人可以指导我吗？我很茫然。

最佳答案

在您的 PHP 代码中:

$result = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($data), 'ecb');

在您的 iOS 代码中:

CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                  keyPtr, kCCKeySizeAES256,
                                  NULL /* initialization vector (optional) */,
                                  [self bytes], dataLength, /* input */
                                  buffer, bufferSize, /* output */
                                  &numBytesEncrypted);

需要明确的是，kCCOptionPKCS7Padding 是 CBC 模式标志，而不是 ECB 模式标志。

我认为这里有两个错误:

1. 您需要从 iOS 中调用 urlencode()(或等效函数)以防止 + 变成空格字符。
2. 您正在加密 CBC 模式和解密 ECB 模式。这会给你不正确的数据。

您需要对算法进行以下更改:

加密

1. 生成一个 16 字节的随机字符串，securely .
2. 将其用作初始化向量 (IV)。
3. 加密后，计算IV和密文的HMAC-SHA256。
4. 在消息中包含 IV 和 HMAC 输出。

解密

1. 重新计算您收到的 IV 和密文的 HMAC-SHA256。
2. 使用 hash_equals() 将其与给定的 HMAC 进行比较。如果失败，则抛出异常。
3. 如果第 2 步通过，则使用 AES-CBC 模式解密(给定 IV)。
4. Use openssl instead of mcrypt .

或者，您可能想切换到 NAChloride或 Swift-Sodium用于加密并将 PHP 更新到 7.2+，并使用 sodium_* 函数进行解密。

关于php - 将IOS中加密的JSON数据发送给PHP解密，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17939239/