cryptokit.verify.swift

let path = Bundle.main.path(forResource: "video", ofType: "mp4")!
let data = FileManager.default.contents(atPath: path)!
let key = SymmetricKey(size: .bits256) // key shared by both parties
let authentication = HMAC<SHA256>.authenticationCode(for: data,
                                                         using: key)
let authenticationData = Data(authentication)

// ~~~~~~ travel accross the network ~~~~~~~

if (HMAC<SHA256>.isValidAuthenticationCode(authenticationData,
                                           authenticating: data,
                                           using: key)) {
    print("Validated ✅")
}