使用哈希进行身份验证

Question

我需要使用我不理解的复杂身份验证过程与 API 建立连接。我知道它涉及多个步骤，我试图模仿它，但我发现文档非常混乱......这个想法是，我向一个端点发出请求，该端点将向我返回一个令牌，我需要使用它来建立websocket连接。我确实得到了一个代码示例，它是在Python中，我不知道它的语法，但我可以把它作为一个指南，把它转换为C#语法。这是蟒蛇代码示例：import time, base64, hashlib, hmac, urllib.request, jsonapi_nonce = bytes(str(int(time.time()*1000)), "utf-8")api_request = urllib.request.Request("https://www.website.com/getToken", b"nonce=%s" % api_nonce)api_request.add_header("API-Key", "API_PUBLIC_KEY")api_request.add_header("API-Sign", base64.b64encode(hmac.new(base64.b64decode("API_PRIVATE_KEY"), b"/getToken" + hashlib.sha256(api_nonce + b"nonce=%s" % api_nonce).digest(), hashlib.sha512).digest()))print(json.loads(urllib.request.urlopen(api_request).read())['result']['token'])所以我试图把它转换成C#，这是我到目前为止得到的代码：    static string apiPublicKey = "API_PUBLIC_KEY";    static string apiPrivateKey = "API_PRIVATE_KEY";    static string endPoint = "https://www.website.com/getToken";    private void authenticate()    {        using (var client = new HttpClient())        {            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;            // CREATE THE URI            string uri = "/getToken";            // CREATE THE NONCE            /// NONCE = unique identifier which must increase in value with each API call            /// in this case we will be using the epoch time            DateTime baseTime = new DateTime(1970, 1, 1, 0, 0, 0);            TimeSpan epoch = CurrentTime - baseTime;            Int64 nonce = Convert.ToInt64(epoch.TotalMilliseconds);            // CREATE THE DATA            string data = string.Format("nonce={0}", nonce);            // CALCULATE THE SHA256 OF THE NONCE            string sha256 = SHA256_Hash(data);            // DECODE THE PRIVATE KEY            byte[] apiSecret = Convert.FromBase64String(apiPrivateKey);            // HERE IS THE HMAC CALCULATION        }    }所以下一部分是我真正挣扎的地方。需要做一些HMAC计算，但我完全迷失在那里。

Answer 1

这里的主要任务是反转SHA-512 HMAC计算。使用日期时间偏移.Now.ToUnix时间毫秒获取API，它将返回一个Unix时间戳毫秒值。然后，这一切都归结为串联字节数组并生成哈希值。我使用硬编码时间只是为了演示结果;每次计算密钥时，您必须取消注释才能获得当前的Unix时间戳毫秒。API-Signnonceapi_noncestring ApiNonce = DateTimeOffset.Now.ToUnixTimeMillisecondsAPI-Sign

蟒蛇生成：API-Sign

import time, base64, hashlib, hmac, urllib.request, json

# Hardcoce API_PRIVATE_KEY base 64 value

API_PRIVATE_KEY = base64.encodebytes(b"some_api_key_1234")

# time_use = time.time()

# Hardcode the time so we can confirm the same result to C#

time_use = 1586096626.919

api_nonce = bytes(str(int(time_use*1000)), "utf-8")

print("API nonce: %s" % api_nonce)

api_request = urllib.request.Request("https://www.website.com/getToken", b"nonce=%s" % api_nonce)

api_request.add_header("API-Key", "API_PUBLIC_KEY_1234")

print("API_PRIVATE_KEY: %s" % API_PRIVATE_KEY)

h256Dig = hashlib.sha256(api_nonce + b"nonce=%s" % api_nonce).digest()

api_sign = base64.b64encode(hmac.new(base64.b64decode(API_PRIVATE_KEY), b"/getToken" + h256Dig, hashlib.sha512).digest())

# api_request.add_header("API-Sign", api_sign)

# print(json.loads(urllib.request.urlopen(api_request).read())['result']['token'])

print("API-Sign: %s" % api_sign)

将输出：

API nonce: b'1586096626919'

API_PRIVATE_KEY: b'c29tZV9hcGlfa2V5XzEyMzQ=\n'

API-Sign: b'wOsXlzd3jOP/+Xa3AJbfg/OM8wLvJgHATtXjycf5EA3tclU36hnKAMMIu0yifznGL7yhBCYEwIiEclzWvOgCgg=='

C# 生成：API-Sign

static string apiPublicKey = "API_PUBLIC_KEY";

// Hardcoce API_PRIVATE_KEY base 64 value

static string apiPrivateKey = Base64EncodeString("some_api_key_1234");

static string endPoint = "https://www.website.com/getToken";

public static void Main()

{

    Console.WriteLine("API-Sign: '{0}'", GenApiSign());

}

static private string GenApiSign()

{

    // string ApiNonce = DateTimeOffset.Now.ToUnixTimeMilliseconds().ToString();

    // Hardcode the time so we can confirm the same result with Python

    string ApiNonce = "1586096626919";

    Console.WriteLine("API nonce: {0}", ApiNonce);

    Console.WriteLine("API_PRIVATE_KEY: '{0}'", apiPrivateKey);

    byte[] ApiNonceBytes = Encoding.Default.GetBytes(ApiNonce);

    byte[] h256Dig = GenerateSHA256(CombineBytes(ApiNonceBytes, Encoding.Default.GetBytes("nonce="), ApiNonceBytes));

    byte[] h256Token = CombineBytes(Encoding.Default.GetBytes("/getToken"), h256Dig);

    string ApiSign = Base64Encode(GenerateSHA512(Base64Decode(apiPrivateKey), h256Token));

    return ApiSign;

}

// Helper functions ___________________________________________________

public static byte[] CombineBytes(byte[] first, byte[] second)

{

    byte[] ret = new byte[first.Length + second.Length];

    Buffer.BlockCopy(first, 0, ret, 0, first.Length);

    Buffer.BlockCopy(second, 0, ret, first.Length, second.Length);

    return ret;

}

public static byte[] CombineBytes(byte[] first, byte[] second, byte[] third)

{

    byte[] ret = new byte[first.Length + second.Length + third.Length];

    Buffer.BlockCopy(first, 0, ret, 0, first.Length);

    Buffer.BlockCopy(second, 0, ret, first.Length, second.Length);

    Buffer.BlockCopy(third, 0, ret, first.Length + second.Length,

                     third.Length);

    return ret;

}

public static byte[] GenerateSHA256(byte[] bytes)

{

    SHA256 sha256 = SHA256Managed.Create();

    return sha256.ComputeHash(bytes);

}

public static byte[] GenerateSHA512(byte[] key, byte[] bytes)

{

    var hash = new HMACSHA512(key);

    var result = hash.ComputeHash(bytes);

    hash.Dispose();

    return result;

}

public static string Base64EncodeString(string plainText)

{

    var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);

    return System.Convert.ToBase64String(plainTextBytes);

}

public static string Base64Encode(byte[] bytes)

{

    return System.Convert.ToBase64String(bytes);

}

public static byte[] Base64Decode(string base64EncodedData)

{

    var base64EncodedBytes = System.Convert.FromBase64String(base64EncodedData);

    return base64EncodedBytes;

}

将输出：

API nonce: 1586096626919

API_PRIVATE_KEY: 'c29tZV9hcGlfa2V5XzEyMzQ='

API-Sign: 'wOsXlzd3jOP/+Xa3AJbfg/OM8wLvJgHATtXjycf5EA3tclU36hnKAMMIu0yifznGL7yhBCYEwIiEclzWvOgCgg=='

您可以看到它的工作原理以及此 .NET 小提琴中的结果。