如何发送NSData作为CCCrypt的关键字和IV [英] How to send NSData as key and IV for CCCrypt

问题描述

我需要AES128使用密钥和IV到16字节的AES块对16字节的数据块进行加密。

我看过的每个CCCrypt示例都输入了（NSString *）键和IV。我的密钥和IV是NSData 16字节。我将NSData转换成十六进制字符串，但结果不正确。当我这样做时，我得到一个32字节的AES块。

所以我的问题是，我需要做什么才能将NSData作为const void *读取到CCCrypt？

$ b （NSData *）键iv：（NSString *）iv数据：（NSData *）theData
{
char keyPtr [kCCKeySizeAES128 + 1];
bzero（keyPtr，sizeof（keyPtr））;
[key getCString：keyPtr maxLength：sizeof（keyPtr）encoding：NSUTF8StringEncoding];

char ivPtr [kCCBlockSizeAES128 + 1];
bzero（ivPtr，sizeof（ivPtr））;
if（iv）{
[iv getCString：ivPtr maxLength：sizeof（ivPtr）encoding：NSUTF8StringEncoding];
}

NSUInteger dataLength = [theData length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void * buffer = malloc（bufferSize）;

size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt（operation，
kCCAlgorithmAES128，
kCCOptionECBMode，
keyPtr，
kCCBlockSizeAES128，
ivPtr，
[theData bytes]
dataLength，
buffer，
bufferSize，
& numBytesEncrypted）;


if（cryptStatus == kCCSuccess）{
return [NSData dataWithBytesNoCopy：buffer length：numBytesEncrypted];
}
free（buffer）;
return nil;
}

解决方案

  +（NSData *）AES128：（NSData *）dataIn 
操作：（CCOperation）操作// kCC加密，解密
键：（NSData *）键
选项：（CCOptions ）选项// kCCOption PKCS7Padding，ECBMode，
 iv：（NSData *）iv 
错误：（NSError **）错误
 {
 CCCryptorStatus ccStatus = kCCSuccess; 
 size_t cryptBytes = 0; 
 NSMutableData * dataOut = [NSMutableData dataWithLength：dataIn.length + kCCBlockSizeAES128]; 
 
 ccStatus = CCCrypt（operation，
 kCCAlgorithmAES，
 options，
 key.bytes，key.length，
 iv.bytes，
 dataIn.length，dataIn.length，
 dataOut.mutableBytes，dataOut.length，
& cryptBytes）; 
 
 if（ccStatus == kCCSuccess）{
 dataOut.length = cryptBytes; 
} 
 else {
 if（error）{
 * error = [NSError errorWithDomain：@kEncryptionError
 code：ccStatus 
 userInfo：nil] ; 
} 
 dataOut = nil; 
} 
 
 return dataOut; 
} 
  

I need to AES128 encrypt a 16 byte block of data using a key and an IV to a 16 byte AES block.

Every CCCrypt example I've seen takes in (NSString *) for key and IV. My Key and IV are NSData 16 bytes. I've converted the NSData into hex strings but the result is not correct. I get an AES block of 32 bytes when I do it that way.

So my question is, what do I have to do to get NSData to be read into CCCrypt as a const void * ?

- (NSData *)AES128Operation:(CCOperation)operation key:(NSString *)key iv:(NSString *)iv theData:(NSData *)theData
{
    char keyPtr[kCCKeySizeAES128 + 1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    char ivPtr[kCCBlockSizeAES128 + 1];
    bzero(ivPtr, sizeof(ivPtr));
    if (iv) {
        [iv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];
    }

    NSUInteger dataLength = [theData length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);

    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(operation,
                                          kCCAlgorithmAES128,
                                          kCCOptionECBMode,
                                          keyPtr,
                                          kCCBlockSizeAES128,
                                          ivPtr,
                                          [theData bytes],
                                          dataLength,
                                          buffer,
                                          bufferSize,
                                          &numBytesEncrypted);


    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }
    free(buffer);
    return nil;
}

解决方案

+ (NSData *)AES128:(NSData *)dataIn
         operation:(CCOperation)operation  // kCC Encrypt, Decrypt
               key:(NSData *)key
           options:(CCOptions)options      // kCCOption PKCS7Padding, ECBMode,
                iv:(NSData *)iv
             error:(NSError **)error
{
    CCCryptorStatus ccStatus   = kCCSuccess;
    size_t          cryptBytes = 0;
    NSMutableData  *dataOut    = [NSMutableData dataWithLength:dataIn.length + kCCBlockSizeAES128];

    ccStatus = CCCrypt( operation,
                       kCCAlgorithmAES,
                       options,
                       key.bytes, key.length,
                       iv.bytes,
                       dataIn.bytes, dataIn.length,
                       dataOut.mutableBytes, dataOut.length,
                       &cryptBytes);

    if (ccStatus == kCCSuccess) {
        dataOut.length = cryptBytes;
    }
    else {
        if (error) {
            *error = [NSError errorWithDomain:@"kEncryptionError"
                                         code:ccStatus
                                     userInfo:nil];
        }
        dataOut = nil;
    }

    return dataOut;
}

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