我现在已经实现了许多TOTP类，它们都生成了错误的输出。下面我发布了我用于最简单的代码。
我希望它能够实现，并且像Google身份验证器一样行事 - 例如代码https://gauth.apps.gbraad.nl/#main。
所以我想要发生的是，在应用程序的前端，用户将输入他的秘密＆＃34; BANANAKEY123＆＃34;转换为＆＃34; IJAU4QKOIFFUKWJRGIZQ ====＆＃34;的基本字符串32。
现在在下面的构造函数中，键将是＆＃34; BANANAKEY123＆＃34;。但由于某种原因，它＆＃39;使用此代码生成与GAuth OTP工具相同的OTP密钥。
唯一的两个合理错误是
var secretKeyBytes = Base32Encode(secretKey);
错误或我的计时功能错误。我检查了两个并且无法找到任何一个中的错误。那么有人可以帮我正确的方向吗？谢谢！
public class Totp
{
private readonly int digits = 6;
private readonly HMACSHA1 hmac;
private readonly HMACSHA256 hmac256;
private readonly Int32 t1 = 30;
internal int mode;
private string secret;
private const string allowedCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
public Totp(string key, int mode)
{
secret = key;
this.mode = mode;
}
// defaults to SHA-1
public Totp(string key)
{
secret = key;
this.mode = 1;
}
public Totp(string base32string, Int32 t1, int digits) : this(base32string)
{
this.t1 = t1;
this.digits = digits;
}
public Totp(string base32string, Int32 t1, int digits, int mode) : this(base32string, mode)
{
this.t1 = t1;
this.digits = digits;
}
public String getCodeString()
{
return GetCode(this.secret, GetInterval(DateTime.UtcNow));
}
private static long GetInterval(DateTime dateTime)
{
TimeSpan elapsedTime = dateTime.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return (long)elapsedTime.TotalSeconds / 30;
}
private static string GetCode(string secretKey, long timeIndex)
{
var secretKeyBytes = Base32Encode(secretKey);
HMACSHA1 hmac = new HMACSHA1(secretKeyBytes);
byte[] challenge = BitConverter.GetBytes(timeIndex);
if (BitConverter.IsLittleEndian) Array.Reverse(challenge);
byte[] hash = hmac.ComputeHash(challenge);
int offset = hash[19] & 0xf;
int truncatedHash = hash[offset] & 0x7f;
for (int i = 1; i < 4; i++)
{
truncatedHash <<= 8;
truncatedHash |= hash[offset + i] & 0xff;
}
truncatedHash %= 1000000;
return truncatedHash.ToString("D6");
}
private static byte[] Base32Encode(string source)
{
var bits = source.ToUpper().ToCharArray().Select(c =>
Convert.ToString(allowedCharacters.IndexOf(c), 2).PadLeft(5, '0')).Aggregate((a, b) => a + b);
return Enumerable.Range(0, bits.Length / 8).Select(i => Convert.ToByte(bits.Substring(i * 8, 8), 2)).ToArray();
}
}
答案 0 :(得分：0)
我已经使用这段代码很长一段时间来生成基于时间的OTP，希望它有所帮助。
using System;
using System.Net;
using System.Security.Cryptography;
using System.Text;
namespace Wteen.Infrastructure.Services
{
/// <summary>
/// An Time Based Implementation of RFC 6248, a variation from the OTP (One Time Password) with, a default code life time of 30 seconds.
/// </summary>
public sealed class TotpAuthenticationService
{
private readonly Encoding _encoding;
private readonly int _length;
private readonly TimeSpan _timestep;
private readonly DateTime _unixEpoch;
/// <summary>
/// Create a new Instance of <see cref="TotpAuthenticationService"/>
/// </summary>
/// <param name="length">The length of the OTP</param>
/// <param name="duration">The peried of time in which the genartion of a OTP with the result with the same value</param>
public TotpAuthenticationService(int length, int duration = 30)
{
_length = length;
_encoding = new UTF8Encoding(false, true);
_timestep = TimeSpan.FromSeconds(duration);
_unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
}
/// <summary>
/// The current time step number
/// </summary>
private ulong CurrentTimeStepNumber => (ulong)(TimeElapsed.Ticks / _timestep.Ticks);
/// <summary>
/// The number of seconds elapsed since midnight UTC of January 1, 1970.
/// </summary>
private TimeSpan TimeElapsed => DateTime.UtcNow - _unixEpoch;
/// <summary>
///
/// </summary>
/// <param name="securityToken"></param>
/// <param name="modifier"></param>
/// <returns></returns>
public int GenerateCode(byte[] securityToken, string modifier = null)
{
if (securityToken == null)
throw new ArgumentNullException(nameof(securityToken));
using (var hmacshA1 = new HMACSHA1(securityToken))
{
return ComputeTotp(hmacshA1, CurrentTimeStepNumber, modifier);
}
}
/// <summary>
/// Validating for codes generated during the current and past code generation <see cref="timeSteps"/>
/// </summary>
/// <param name="securityToken">User's secerct</param>
/// <param name="code">The code to validate</param>
/// <param name="timeSteps">The number of time steps the <see cref="code"/> could be validated for.</param>
/// <param name="channel">Possible channels could be user's email or mobile number where the code will be sent to</param>
/// <returns></returns>
public bool ValidateCode(byte[] securityToken, int code, int timeSteps, string channel = null)
{
if (securityToken == null)
throw new ArgumentNullException(nameof(securityToken));
using (var hmacshA1 = new HMACSHA1(securityToken))
{
for (var index = -timeSteps; index <= timeSteps; ++index)
if (ComputeTotp(hmacshA1, CurrentTimeStepNumber + (ulong)index, channel) == code)
return true;
}
return false;
}
private byte[] ApplyModifier(byte[] input, string modifier)
{
if (string.IsNullOrEmpty(modifier))
return input;
var bytes = _encoding.GetBytes(modifier);
var numArray = new byte[checked(input.Length + bytes.Length)];
Buffer.BlockCopy(input, 0, numArray, 0, input.Length);
Buffer.BlockCopy(bytes, 0, numArray, input.Length, bytes.Length);
return numArray;
}
private int ComputeTotp(HashAlgorithm algorithm, ulong timestepNumber, string modifier)
{
var bytes = BitConverter.GetBytes(IPAddress.HostToNetworkOrder((long)timestepNumber));
var hash = algorithm.ComputeHash(ApplyModifier(bytes, modifier));
var index = hash[hash.Length - 1] & 15;
return (((hash[index] & sbyte.MaxValue) << 24) | ((hash[index + 1] & byte.MaxValue) << 16) | ((hash[index + 2] & byte.MaxValue) << 8) | (hash[index + 3] & byte.MaxValue)) % (int)Math.Pow(10, _length);
}
}
}