使用密钥和消息在swift中创建哈希 [英] Create hash in swift using key and message

问题描述

我想使用swift中的键创建字符串的SHA1 hmac哈希。在obj-c中我使用了它并且效果很好：

I want to create an SHA1 hmac hash of a string using a key in swift. In obj-c I used this and it worked great:

+(NSString *)sha1FromMessage:(NSString *)message{

    const char *cKey  = [API_KEY cStringUsingEncoding:NSASCIIStringEncoding];
    const char *cData = [message cStringUsingEncoding:NSUTF8StringEncoding];

    NSLog(@"%s", cData);

    unsigned char cHMAC[CC_SHA1_DIGEST_LENGTH];

    CCHmac(kCCHmacAlgSHA1, cKey, strlen(cKey), cData, strlen(cData), cHMAC);
    NSData *HMACData = [NSData dataWithBytes:cHMAC length:sizeof(cHMAC)];

    const unsigned char *buffer = (const unsigned char *)[HMACData bytes];
    NSMutableString *HMAC = [NSMutableString stringWithCapacity:HMACData.length * 2];

    for (int i = 0; i < HMACData.length; ++i){
        [HMAC appendFormat:@"%02hhx", buffer[i]];
    }
    return HMAC;
}

但是现在我很难把它翻译成swift。这是我到目前为止：

However now I am having a hard time to translate this into swift. This is what I have so far:

static func sha1FromMessage(message: String){

        let cKey = RestUtils.apiKey.cStringUsingEncoding(NSASCIIStringEncoding)!
        let cData = message.cStringUsingEncoding(NSUTF8StringEncoding)!
        let cHMAC = [CUnsignedChar](count: Int(CC_SHA1_DIGEST_LENGTH), repeatedValue: 0)

        CCHmac(kCCHmacAlgSHA1, cKey, cKey.count, cData, cData.count, cHMAC)
        ...
}

此行

CCHmac(kCCHmacAlgSHA1, cKey, cKey.count, cData, cData.count, cHMAC)

已经给我一个错误 Int不能转换为CCHmacAlgorithm 。任何想法如何将obj-c代码翻译成swift？

already gives me an error Int is not convertible to CCHmacAlgorithm. Any ideas how to translate the obj-c code to swift?

推荐答案

CCHmac的最后一个参数（）函数的类型为 UnsafeMutablePointer< Void> ，因为
就是写入的结果。您必须将 cHMAC 声明为变量
并将其作为输入输出表达式传递给&安培; 。此外，某些类型的转换
是必要的：

The last parameter of the CCHmac() function has the type UnsafeMutablePointer<Void> because that's where the result is written to. You have to declare cHMAC as variable and pass it as an in-out expression with &. In addition, some type conversions are necessary:

var cHMAC = [CUnsignedChar](count: Int(CC_SHA1_DIGEST_LENGTH), repeatedValue: 0)
CCHmac(CCHmacAlgorithm(kCCHmacAlgSHA1), cKey, UInt(cKey.count), cData, UInt(cData.count), &cHMAC)

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