使用 iv 的 AES128 CTR 加密

Question

我想用 iv 和密钥实现 AES128 CTR。我正在寻找如何以最佳方式做到这一点而不是重新发明轮子的任何建议。

我为这个 RNCryptor 找到了很好的库，但看起来那里不支持这个 aes。

我也测试了 this 方法，但看起来这不是点击率。

编辑

我使用了@zaph 的 zpproach

NSData *result = [NSData cryptData:dataStr
                         operation:kCCEncrypt
                              mode:kCCModeCTR
                         algorithm:kCCAlgorithmAES128
                           padding:ccNoPadding
                         keyLength:kCCKeySizeAES128
                                iv:ivHex
                               key:keyHex
                             error:&error];

但收到 CCCryptorCreate status: -4305

刚刚在资源中找到

@constant kCCUnimplemented Function not implemented for the current algorithm.

Link

Answer 1

也许您正在寻找 CryptoSwift 图书馆。支持AES和CTR。

另一个流行的加密库是 libsodium，但我不确定它是否支持 CTR。

Answer 2

您需要使用 CommonCrypto 但不是一次性 CCCrypt 版本，而是完整的 CCCryptorCreateWithMode、CCCryptorUpdate、CCCryptorFinal 和 CCCryptorRelease使用模式 kCCModeCTR 版本。

这是我的示例代码，它可能不符合您的需要，您必须决定柜台 (IV) 表格。

#import <CommonCrypto/CommonCrypto.h>

+ (NSData *)cryptData:(NSData *)dataIn
            operation:(CCOperation)operation  // kCC Encrypt, Decrypt
                 mode:(CCMode)mode            // kCCMode ECB, CBC, CFB, CTR, OFB, RC4, CFB8
            algorithm:(CCAlgorithm)algorithm  // CCAlgorithm AES DES, 3DES, CAST, RC4, RC2, Blowfish
              padding:(CCPadding)padding      // cc NoPadding, PKCS7Padding
            keyLength:(size_t)keyLength       // kCCKeySizeAES 128, 192, 256
                   iv:(NSData *)iv            // CBC, CFB, CFB8, OFB, CTR
                  key:(NSData *)key
                error:(NSError **)error
{
    if (key.length != keyLength) {
        NSLog(@"CCCryptorArgument key.length: %lu != keyLength: %zu", (unsigned long)key.length, keyLength);
        if (error) {
            *error = [NSError errorWithDomain:@"kArgumentError key length" code:key.length userInfo:nil];
        }
        return nil;
    }

    size_t dataOutMoved = 0;
    size_t dataOutMovedTotal = 0;
    CCCryptorStatus ccStatus = 0;
    CCCryptorRef cryptor = NULL;

    ccStatus = CCCryptorCreateWithMode(operation, mode, algorithm,
                                       padding,
                                       iv.bytes, key.bytes,
                                       keyLength,
                                       NULL, 0, 0, // tweak XTS mode, numRounds
                                       kCCModeOptionCTR_BE, // CCModeOptions
                                       &cryptor);

    if (cryptor == 0 || ccStatus != kCCSuccess) {
        NSLog(@"CCCryptorCreate status: %d", ccStatus);
        if (error) {
            *error = [NSError errorWithDomain:@"kCreateError" code:ccStatus userInfo:nil];
        }
        CCCryptorRelease(cryptor);
        return nil;
    }

    size_t dataOutLength = CCCryptorGetOutputLength(cryptor, dataIn.length, true);
    NSMutableData *dataOut = [NSMutableData dataWithLength:dataOutLength];
    char *dataOutPointer = (char *)dataOut.mutableBytes;

    ccStatus = CCCryptorUpdate(cryptor,
                               dataIn.bytes, dataIn.length,
                               dataOutPointer, dataOutLength,
                               &dataOutMoved);
    dataOutMovedTotal += dataOutMoved;

    if (ccStatus != kCCSuccess) {
        NSLog(@"CCCryptorUpdate status: %d", ccStatus);
        if (error) {
            *error = [NSError errorWithDomain:@"kUpdateError" code:ccStatus userInfo:nil];
        }
        CCCryptorRelease(cryptor);
        return nil;
    }

    ccStatus = CCCryptorFinal(cryptor,
                              dataOutPointer + dataOutMoved, dataOutLength - dataOutMoved,
                              &dataOutMoved);
    if (ccStatus != kCCSuccess) {
        NSLog(@"CCCryptorFinal status: %d", ccStatus);
        if (error) {
            *error = [NSError errorWithDomain:@"kFinalError" code:ccStatus userInfo:nil];
        }
        CCCryptorRelease(cryptor);
        return nil;
    }

    CCCryptorRelease(cryptor);

    dataOutMovedTotal += dataOutMoved;
    dataOut.length = dataOutMovedTotal;

    return dataOut;
}

示例调用：

NSData *dataIn  = [@"DataInDataInData" dataUsingEncoding: NSUTF8StringEncoding];
NSData *key     = [@"KeyKeyKeyKeyKeyK" dataUsingEncoding: NSUTF8StringEncoding];
NSData *counter = [@"CounterCounterCo" dataUsingEncoding: NSUTF8StringEncoding];
NSError *error;
NSData *encrpted = [Crypto
                    cryptData:dataIn
                    operation:kCCEncrypt
                    mode:kCCModeCTR
                    algorithm:kCCAlgorithmAES
                    padding:ccNoPadding
                    keyLength:kCCKeySizeAES128
                    iv:counter
                    key:key
                    error:&error];
NSLog(@"encrypted: %@", encrpted);

输出：encrypted: 064e8073 76973eba 3192474f 9831db34

使用 iv 的 AES128 CTR 加密

AES128 CTR encryption with iv

encryption

aes

ios

commoncrypto