InformationSecurityConnectWorkshop.swift

// 取得 Query 的 body string
let dateString = query(dict) //使用預設的 URLEncoding.default 產生Body Encode
        print(dateString)
        
// 以 sha256 把 key 和 body 作成簽名     
let keybytes: Array<UInt8> = input0.text!.bytes
let signature = try! HMAC(key: keybytes, variant: .sha256).authenticate(dateString.bytes)
print("signature \(signature.toHexString())")

// 將簽名跟 key id 放在 Header，傳出去 
let headers: HTTPHeaders = [
    "x-keyid": inputkeyID.text!,
    "x-signature":signature.toHexString()
]