使用CCHmac（）生成HMAC swift sdk8.3 [英] Generate a HMAC swift sdk8.3 using CCHmac()

问题描述

在SDK8.3之前我以这种方式生成我的hmac。现在我在CCHmac（）函数上出错了。由于我是初学者，我无法弄清楚如何解决它。在此先感谢您的帮助！

Before SDK8.3 I was generating my hmac this way. Now I get an error on the CCHmac() function. Since I'm a beginner I can't figure out how to fix it. Thanks in advance for your help!

xcode警告：不能使用类型的参数列表（UInt32，[CChar]）来'CCHmac'？ ，UInt，[CChar] ?, UInt，inout [（CUnsignedChar）]

xcode warning: cannot involke 'CCHmac' with an argument list of type (UInt32, [CChar]?, UInt, [CChar]?, UInt, inout[(CUnsignedChar)]

func generateHMAC(key: String, data: String) -> String {

    let cKey = key.cStringUsingEncoding(NSUTF8StringEncoding)
    let cData = data.cStringUsingEncoding(NSUTF8StringEncoding)

    var result = [CUnsignedChar](count: Int(CC_SHA512_DIGEST_LENGTH), repeatedValue: 0)
    CCHmac(CCHmacAlgorithm(kCCHmacAlgSHA512), cKey, strlen(cKey!), cData, strlen(cData!), &result)


    let hash = NSMutableString()
    for var i = 0; i < result.count; i++ {
        hash.appendFormat("%02hhx", result[i])
    }

    return hash as String
}

推荐答案

问题是 strlen 返回 UInt ，而 CCHmac 的长度参数是 Int s。

The problem is that strlen returns a UInt, while CCHmac’s length arguments are Ints.

虽然你可以做一些强制，你也可以只使用两个数组的 count 属性，而不是调用 strlen 。

While you could do some coercion, you may as well just use the count property of the two arrays rather than calling strlen.

func generateHMAC(key: String, data: String) -> String {

    var result: [CUnsignedChar]
    if let cKey = key.cStringUsingEncoding(NSUTF8StringEncoding),
           cData = data.cStringUsingEncoding(NSUTF8StringEncoding)
    {
        let algo  = CCHmacAlgorithm(kCCHmacAlgSHA512)
        result = Array(count: Int(CC_SHA512_DIGEST_LENGTH), repeatedValue: 0)

        CCHmac(algo, cKey, cKey.count-1, cData, cData.count-1, &result)
    }
    else {
        // as @MartinR points out, this is in theory impossible 
        // but personally, I prefer doing this to using `!`
        fatalError("Nil returned when processing input strings as UTF8")
    }

    let hash = NSMutableString()
    for val in result {
        hash.appendFormat("%02hhx", val)
    }

    return hash as String
}

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