Minimal way to get HMAC SHA512 in swift 3.1

Question

I'm coding an app using xcode and swift 3.1

I need to create hmac sha512 hash for my api call to the server.

I konw there are various frameworks like CryptoSwift that provide us with such feature.

However I am interested to know if it's possible in native xcode / swift 3.1 without the use of any libraries or frameworks.

If not then why not?

Also, if I do need to use the library, what's the minimal method to get hmac sha512 based library code only?

Thanks.

Sure it's possible. It's just math. Look up the algorithm and write it. :) — Tom Harrington, Jun 07 '17 at 00:36
Or pull it out of CryptoSwift, which includes SHA-512 in Swift without a framework underneath it. https://github.com/krzyzanowskim/CryptoSwift/blob/master/Sources/CryptoSwift/SHA2.swift — Rob Napier, Feb 12 '18 at 23:52

score 3 · Answer 1 · answered Feb 12 '18 at 19:45

You should definitely use CommonCrypto because it is already available on every device, well tested and fast. You just need to add a bridging header containing

#import <CommonCrypto/CommonCrypto.h>

You can look up here how to add the bridging header.

You then can compute your HMAC with a simple extension (Swift 4):

extension String {

    func hmac(key: String) -> String {
        var digest = [UInt8](repeating: 0, count: Int(CC_SHA256_DIGEST_LENGTH))
        CCHmac(CCHmacAlgorithm(kCCHmacAlgSHA256), key, key.count, self, self.count, &digest)
        let data = Data(bytes: digest)
        return data.map { String(format: "%02hhx", $0) }.joined()
    }

}

Example:

let result = "test".hmac(key: "test")

Result:

88cd2108b5347d973cf39cdf9053d7dd42704876d8c9a9bd8e2d168259d3ddf7

Minimal way to get HMAC SHA512 in swift 3.1

1 Answers1