我正在寻找有关如何在 .NET 应用程序中使用Google Authenticator的教程。这是否存在，如果存在，我在哪里可以找到它？
我了解这可用于向您自己的应用程序添加双因素身份验证。
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6 回答
48
在使用 Google Authenticator 时，我遇到了这个问题，特别是 Espo 贡献的代码。我个人对从 Java 到 C# 的转换并不满意，所以我想我会分享我的版本。除了大量重构代码：
- 引入了对小端字节顺序的检查，并在必要时转换为大端。
- 为 HMAC 密钥引入了参数。
有关配置 url 格式的更多信息，另请参阅：https ://github.com/google/google-authenticator/wiki/Key-Uri-Format
如果您愿意，请随意使用，并感谢 Espo 的初步工作。
using System;
using System.Globalization;
using System.Net;
using System.Security.Cryptography;
using System.Text;
public class GoogleAuthenticator
{
const int IntervalLength = 30;
const int PinLength = 6;
static readonly int PinModulo = (int)Math.Pow(10, PinLength);
static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
/// <summary>
/// Number of intervals that have elapsed.
/// </summary>
static long CurrentInterval
{
get
{
var ElapsedSeconds = (long)Math.Floor((DateTime.UtcNow - UnixEpoch).TotalSeconds);
return ElapsedSeconds/IntervalLength;
}
}
/// <summary>
/// Generates a QR code bitmap for provisioning.
/// </summary>
public byte[] GenerateProvisioningImage(string identifier, byte[] key, int width, int height)
{
var KeyString = Encoder.Base32Encode(key);
var ProvisionUrl = Encoder.UrlEncode(string.Format("otpauth://totp/{0}?secret={1}&issuer=MyCompany", identifier, KeyString));
var ChartUrl = string.Format("https://chart.apis.google.com/chart?cht=qr&chs={0}x{1}&chl={2}", width, height, ProvisionUrl);
using (var Client = new WebClient())
{
return Client.DownloadData(ChartUrl);
}
}
/// <summary>
/// Generates a pin for the given key.
/// </summary>
public string GeneratePin(byte[] key)
{
return GeneratePin(key, CurrentInterval);
}
/// <summary>
/// Generates a pin by hashing a key and counter.
/// </summary>
static string GeneratePin(byte[] key, long counter)
{
const int SizeOfInt32 = 4;
var CounterBytes = BitConverter.GetBytes(counter);
if (BitConverter.IsLittleEndian)
{
//spec requires bytes in big-endian order
Array.Reverse(CounterBytes);
}
var Hash = new HMACSHA1(key).ComputeHash(CounterBytes);
var Offset = Hash[Hash.Length - 1] & 0xF;
var SelectedBytes = new byte[SizeOfInt32];
Buffer.BlockCopy(Hash, Offset, SelectedBytes, 0, SizeOfInt32);
if (BitConverter.IsLittleEndian)
{
//spec interprets bytes in big-endian order
Array.Reverse(SelectedBytes);
}
var SelectedInteger = BitConverter.ToInt32(SelectedBytes, 0);
//remove the most significant bit for interoperability per spec
var TruncatedHash = SelectedInteger & 0x7FFFFFFF;
//generate number of digits for given pin length
var Pin = TruncatedHash%PinModulo;
return Pin.ToString(CultureInfo.InvariantCulture).PadLeft(PinLength, '0');
}
#region Nested type: Encoder
static class Encoder
{
/// <summary>
/// Url Encoding (with upper-case hexadecimal per OATH specification)
/// </summary>
public static string UrlEncode(string value)
{
const string UrlEncodeAlphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~";
var Builder = new StringBuilder();
for (var i = 0; i < value.Length; i++)
{
var Symbol = value[i];
if (UrlEncodeAlphabet.IndexOf(Symbol) != -1)
{
Builder.Append(Symbol);
}
else
{
Builder.Append('%');
Builder.Append(((int)Symbol).ToString("X2"));
}
}
return Builder.ToString();
}
/// <summary>
/// Base-32 Encoding
/// </summary>
public static string Base32Encode(byte[] data)
{
const int InByteSize = 8;
const int OutByteSize = 5;
const string Base32Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
int i = 0, index = 0;
var Builder = new StringBuilder((data.Length + 7)*InByteSize/OutByteSize);
while (i < data.Length)
{
int CurrentByte = data[i];
int Digit;
//Is the current digit going to span a byte boundary?
if (index > (InByteSize - OutByteSize))
{
int NextByte;
if ((i + 1) < data.Length)
{
NextByte = data[i + 1];
}
else
{
NextByte = 0;
}
Digit = CurrentByte & (0xFF >> index);
index = (index + OutByteSize)%InByteSize;
Digit <<= index;
Digit |= NextByte >> (InByteSize - index);
i++;
}
else
{
Digit = (CurrentByte >> (InByteSize - (index + OutByteSize))) & 0x1F;
index = (index + OutByteSize)%InByteSize;
if (index == 0)
{
i++;
}
}
Builder.Append(Base32Alphabet[Digit]);
}
return Builder.ToString();
}
}
#endregion
}
于 2012-09-13T01:44:44.923 回答
26
要使用 Google Authenticator 添加 Google 两因素身份验证，您需要以下内容
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Security.Cryptography;
using System.Text;
using System.Web.Profile;
using System.Web.Security;
using Google.Authenticator;
获取 Google.Authenticator；检查这里https://www.nuget.org/packages/GoogleAuthenticator
现在设置谷歌身份验证。
TwoFactorAuthenticator tfa = new TwoFactorAuthenticator();
var setupInfo = tfa.GenerateSetupCode("Name of the app", "More info ABout the App", "SuperSecretKeyGoesHere", 300 , 300); //the width and height of the Qr Code in pixels
string qrCodeImageUrl = setupInfo.QrCodeSetupImageUrl; // assigning the Qr code information + URL to string
string manualEntrySetupCode = setupInfo.ManualEntryKey; // show the Manual Entry Key for the users that don't have app or phone
Image1.ImageUrl = qrCodeImageUrl;// showing the qr code on the page "linking the string to image element"
Label1.Text = manualEntrySetupCode; // showing the manual Entry setup code for the users that can not use their phone
您可以将 SuperSecretKeyGoesHere 更改为您想要的任何值，但请确保它超过 10 个字符，否则生成的手动输入密钥将不起作用。现在您可以使用文本框和按钮单击来检查用户输入
此位将查看用户条目并查看其是否正常
string user_enter=TextBox1.Text;
TwoFactorAuthenticator tfa = new TwoFactorAuthenticator();
bool isCorrectPIN = tfa.ValidateTwoFactorPIN("SuperSecretKeyGoesHere", user_enter);
if (isCorrectPIN == true)
{
Label2.Text = "i am cool";
}
else
{
Label2.Text = "i am Fool";
}
于 2017-06-16T09:13:01.660 回答
16
经过一些研究和测试，我创建了自己的“概念验证”，说明如何生成 QR 图像，从手机上扫描，然后验证手机上的密码是否正确。如果有人想加入，也许这可以作为图书馆进一步发展？代码可以在这里找到：
于 2011-06-21T12:48:32.767 回答
7
这个问题要求提供一个教程，其他答案我感觉不到，
一个可以在以下位置找到：
http://www.codeproject.com/Articles/403355/Implementing-Two-Factor-Authentication-in-ASP-NET
本教程由 Rick Bassham 编写，涵盖以下信息：
“什么是双重身份验证”“什么是 Google 身份验证器”“它是如何工作的”
然后解释如何实现代码：
“基于计数器的一次性密码生成”“基于时间的一次性密码生成”
并在下面提供了使用 Visual Studio 2010 的完整教程：
“我该如何使用它”
于 2013-11-08T12:53:43.157 回答
3
您可以运行这个简单的控制台应用程序来了解如何验证一次性令牌代码。请注意，我们需要先从Nuget 包安装库Otp.Net 。
static string secretKey = "JBSWY3DPEHPK3PXP"; //add this key to your Google Authenticator app
private static void Main(string[] args)
{
var bytes = Base32Encoding.ToBytes(secretKey);
var totp = new Totp(bytes);
while (true)
{
Console.Write("Enter your code from Google Authenticator app: ");
string userCode = Console.ReadLine();
//Generate one time token code
string tokenInApp = totp.ComputeTotp();
int remainingSeconds = totp.RemainingSeconds();
if (userCode.Equals(tokenInApp)
&& remainingSeconds > 0)
{
Console.WriteLine("Success!");
}
else
{
Console.WriteLine("Failed. Try again!");
}
}
}
于 2019-01-16T12:31:13.353 回答
2
我没有找到教程，但似乎编写一个端口不会那么难。它是一个 Java 应用程序，基于现有标准 (HMAC SHA1)。
有关非 GUI 胆量的详细信息，请参阅此页面：
并查看这些页面以获取有关移植的信息以及现有（非官方）Silverlight 移植：
于 2011-06-21T08:00:04.253 回答