如何在 Swift 中获得与 Python 中相同的 HMAC-SHA512 签名？

Question

我的目标是使用 Swift 与（经过验证的）Kraken API 进行交互。 Kraken API 网站上有一个使用 Python 的示例，我正在尝试在 Swift 中复制它。然而，我得到的最终加密签名与 Python 中的不同。我究竟做错了什么？任何帮助将非常感激。 顺便说一句，我正在使用 Swift CryptoKit 库。

Python 代码（从 Kraken API 文档复制）：

import urllib.parse
import hashlib
import hmac
import base64

def get_kraken_signature(urlpath, data, secret):

    postdata = urllib.parse.urlencode(data)
    encoded = (str(data['nonce']) + postdata).encode()
    message = urlpath.encode() + hashlib.sha256(encoded).digest()

    mac = hmac.new(base64.b64decode(secret), message, hashlib.sha512)
    sigdigest = base64.b64encode(mac.digest())
    return sigdigest.decode()

api_sec = "kQH5HW/8p1uGOVjbgWA7FunAmGO8lsSUXNsu3eow76sz84Q18fWxnyRzBHCd3pd5nE9qa99HAZtuZuj6F1huXg=="

data = {
    "nonce": "1616492376594",
    "ordertype": "limit",
    "pair": "XBTUSD",
    "price": 37500,
    "type": "buy",
    "volume": 1.25
}

signature = get_kraken_signature("/0/private/AddOrder", data, api_sec)
print("API-Sign: {}".format(signature))
#Output: 4/dpxb3iT4tp/ZCVEwSnEsLxx0bqyhLpdfOpc6fn7OR8+UClSV5n9E6aSS8MPtnRfp32bAb0nmbRn6H8ndwLUQ==
#This output is the expected output, as Kraken states on their website

我的 Swift 代码：

import CryptoKit
func encryptMsg() -> String {
    let privateKey = "kQH5HW/8p1uGOVjbgWA7FunAmGO8lsSUXNsu3eow76sz84Q18fWxnyRzBHCd3pd5nE9qa99HAZtuZuj6F1huXg=="
    let payload = "1616492376594nonce=1616492376594&ordertype=limit&pair=XBTUSD&price=37500&type=buy&volume=1.25"
    let apiPath = "/0/private/AddOrder"
    var payload2 = apiPath
    
    // Sha256Digest
    let sha256Digest: SHA256Digest = SHA256.hash(data: Data(payload.utf8))
    debugPrint(sha256Digest)
    // Output: 23a1c1b34c6a11d641af0f24684896cb90f66fb991125c83dc357bdc3dc146f1
    
    // Convert sha256Digest from hex to ascii
    for element in sha256Digest {
        payload2.append(Character(UnicodeScalar(Int(element.description)!)!))
    }
    debugPrint(payload2)
    // Swift : /0/private/AddOrder#¡Á³Lj\u{11}ÖA¯\u{0F}$hHËöo¹\u{12}\\Ü5{Ü=ÁFñ
    // Python: /0/private/AddOrder#\xa1\xc1\xb3Lj\x11\xd6A\xaf\x0f$hH\x96\xcb\x90\xf6o\xb9\x91\x12\\\x83\xdc5{\xdc=\xc1F\xf1
    // Swift output identical to Python output
    
    // Private key
    debugPrint(Data(base64Encoded: privateKey)!.map { String(format: "%02x", $0) }.joined())
    // Swift : 9101f91d6ffca75b863958db81603b16e9c09863bc96c4945cdb2eddea30efab33f38435f1f5b19f247304709dde97799c4f6a6bdf47019b6e66e8fa17586e5e
    // Python: \x91\x01\xf9\x1do\xfc\xa7[\x869X\xdb\x81`;\x16\xe9\xc0\x98c\xbc\x96\xc4\x94\\\xdb.\xdd\xea0\xef\xab3\xf3\x845\xf1\xf5\xb1\x9f$s\x04p\x9d\xde\x97y\x9cOjk\xdfG\x01\x9bnf\xe8\xfa\x17Xn^
    // Swift output identical to Python output
    let key = SymmetricKey(data: Data(base64Encoded: privateKey)!)
    
    // SHA512 digest and Hmac construction
    var hmacSHA512 = HMAC<SHA512>.authenticationCode(for: Data(payload2.utf8), using: key)
    debugPrint(hmacSHA512)
    // Swift : e82d03bb76af28c9bb55dfc460bf8a0f64d30d0e55307bc5236f5d0581bf8864bce237238d4b7cc3c832a7e2545b1d0f70794545ce76d1bd656c13b054ea54da
    // Python: \xe3\xf7i\xc5\xbd\xe2O\x8bi\xfd\x90\x95\x13\x04\xa7\x12\xc2\xf1\xc7F\xea\xca\x12\xe9u\xf3\xa9s\xa7\xe7\xec\xe4|\xf9@\xa5I^g\xf4N\x9aI/\x0c>\xd9\xd1~\x9d\xf6l\x06\xf4\x9ef\xd1\x9f\xa1\xfc\x9d\xdc\x0bQ
    // Swift output different from Python output
    
    let finalSignature = Data(hmacSHA512).base64EncodedString()
    debugPrint(finalSignature)
    // Swift : 6C0Du3avKMm7Vd/EYL+KD2TTDQ5VMHvFI29dBYG/iGS84jcjjUt8w8gyp+JUWx0PcHlFRc520b1lbBOwVOpU2g==
    // Python: 4/dpxb3iT4tp/ZCVEwSnEsLxx0bqyhLpdfOpc6fn7OR8+UClSV5n9E6aSS8MPtnRfp32bAb0nmbRn6H8ndwLUQ==
    // Final result: Swift output different from Python output
    
    return finalSignature
}

Answer 1

要在 Swift 中实现与 Python 中相同的 HMAC-SHA512 签名，您需要确保两种语言遵循相同的步骤并使用相同的输入。

import CryptoKit

func getKrakenSignature() -> String {
    let privateKey = "kQH5HW/8p1uGOVjbgWA7FunAmGO8lsSUXNsu3eow76sz84Q18fWxnyRzBHCd3pd5nE9qa99HAZtuZuj6F1huXg=="
    let payload = "nonce=1616492376594&ordertype=limit&pair=XBTUSD&price=37500&type=buy&volume=1.25"
    let apiPath = "/0/private/AddOrder"
    let nonce = "1616492376594"
    
    // Constructing the message
    let message = (apiPath + SHA256.hash(data: Data(payload.utf8)).compactMap { String(format: "%02x", $0) }.joined()).data(using: .utf8)!
    
    // Creating HMAC-SHA512 signature
    let key = SymmetricKey(data: Data(base64Encoded: privateKey)!)
    let hmacSHA512 = HMAC<SHA512>.authenticationCode(for: message, using: key)
    
    // Converting HMAC to base64-encoded string
    let finalSignature = Data(hmacSHA512).base64EncodedString()
    
    return finalSignature
}

print("API-Sign: \(getKrakenSignature())")

用于 HMAC 的消息应在 Python 和 Swift 中以相同的方式构造。确保消息包含 URL 路径，后跟编码有效负载的 SHA256 摘要。