完善2FA相关功能 第一部分 (#57)

Api/Utility/General.cs

@@ -1,6 +1,7 @@
 using System.Collections;
 using System.Net.NetworkInformation;
 using System.Security.Cryptography;
+using System.Text;
 using System.Text.Json;
 using System.Text.RegularExpressions;
 using Milimoe.FunGame.Core.Library.Common.Architecture;
@@ -281,7 +282,7 @@ namespace Milimoe.FunGame.Core.Api.Utility
     /// <summary>
     /// 使用HMACSHA512算法加密
     /// </summary>
-    internal class Encryption
+    public class Encryption
     {
         /// <summary>
         /// 使用HMACSHA512算法加密
@@ -299,6 +300,36 @@ namespace Milimoe.FunGame.Core.Api.Utility
             string Hmac = BitConverter.ToString(Hash).Replace("-", "");
             return Hmac.ToLower();
         }
+
+        /// <summary>
+        /// 使用RSA算法加密
+        /// </summary>
+        /// <param name="PlainText">明文</param>
+        /// <param name="PublicKey">公钥</param>
+        /// <returns></returns>
+        public static string RSAEncrypt(string PlainText, string PublicKey)
+        {
+            byte[] Plain = Encoding.UTF8.GetBytes(PlainText);
+            using RSACryptoServiceProvider RSA = new();
+            RSA.FromXmlString(PublicKey);
+            byte[] Encrypted = RSA.Encrypt(Plain, false);
+            return Convert.ToBase64String(Encrypted);
+        }
+
+        /// <summary>
+        /// 使用RSA算法解密
+        /// </summary>
+        /// <param name="SecretText">密文</param>
+        /// <param name="PrivateKey">私钥</param>
+        /// <returns></returns>
+        public static string RSADecrypt(string SecretText, string PrivateKey)
+        {
+            byte[] Encrypted = Convert.FromBase64String(SecretText);
+            using RSACryptoServiceProvider RSA = new();
+            RSA.FromXmlString(PrivateKey);
+            byte[] Decrypted = RSA.Decrypt(Encrypted, false);
+            return Encoding.UTF8.GetString(Decrypted);
+        }
     }
 
     public static class StringExtension

Api/Utility/TFA.cs

@@ -1,46 +0,0 @@
-namespace Milimoe.FunGame.Core.Api.Utility
-{
-    /// <summary>
-    /// aka 2FA
-    /// </summary>
-    public class TFA
-    {
-        private readonly Dictionary<string, string> TFACodes = new();
-
-        public virtual bool IsAvailable(string username)
-        {
-            return true;
-        }
-
-        public string GetTFACode(string username)
-        {
-            string code = TFACodes.ContainsKey(username) ? TFACodes[username] : Verification.CreateVerifyCode(Library.Constant.VerifyCodeType.MixVerifyCode, 5);
-            TaskUtility.RunTimer(() =>
-            {
-                // 十分钟后删除此码
-                TFACodes.Remove(username, out _);
-            }, 1000 * 10 * 60);
-            return code;
-        }
-
-        public bool Authenticate(string username, string code, out string msg)
-        {
-            msg = "";
-            if (!IsAvailable(username))
-            {
-                msg = "此账号不需要双重认证。";
-                return false;
-            }
-            if (TFACodes.ContainsKey(username) && TFACodes.TryGetValue(username, out string? checkcode) && checkcode != null && checkcode == code)
-            {
-                TFACodes.Remove(username);
-                return true;
-            }
-            else
-            {
-                msg = "验证码错误或已过期。";
-                return false;
-            }
-        }
-    }
-}

Api/Utility/TwoFactorAuthenticator.cs

@@ -0,0 +1,185 @@
+using System.Security.Cryptography;
+using System.Text;
+using Milimoe.FunGame.Core.Api.Transmittal;
+
+namespace Milimoe.FunGame.Core.Api.Utility
+{
+    /// <summary>
+    /// Aka. 2FA 双重认证 双因素身份验证
+    /// </summary>
+    public class TwoFactorAuthenticator
+    {
+        private readonly SQLHelper SQLHelper;
+
+        public TwoFactorAuthenticator(SQLHelper SQLHelper)
+        {
+            this.SQLHelper = SQLHelper;
+        }
+
+        /// <summary>
+        /// 检查账号是否需要2FA
+        /// </summary>
+        /// <param name="username"></param>
+        /// <returns></returns>
+        public virtual bool IsAvailable(string username)
+        {
+            return true;
+        }
+
+        /// <summary>
+        /// 2FA验证
+        /// </summary>
+        /// <param name="username"></param>
+        /// <param name="code"></param>
+        /// <param name="msg"></param>
+        /// <returns></returns>
+        public bool Authenticate(string username, string code)
+        {
+            // TODO
+            // 使用username获取此账号记录在案的2FAKey，获取此时间戳内的验证码是否一致。
+            SQLHelper.Execute();
+            return true;
+        }
+
+        /// <summary>
+        /// 每30秒刷新
+        /// </summary>
+        private const int INTERVAL_SECONDS = 30;
+
+        /// <summary>
+        /// 6位数字2FA验证码
+        /// </summary>
+        private const int DIGITS = 6;
+
+        /// <summary>
+        /// 创键私钥，用于绑定账号，并生成两个文件，需要用户保存
+        /// </summary>
+        public static void CreateSecretKey()
+        {
+            string publicpath = "public.key"; // 公钥（密文）文件路径
+            string privatepath = "private.key"; // 私钥文件路径
+
+            // 创建RSA实例
+            using RSACryptoServiceProvider rsa = new();
+
+            // 获取公钥和私钥
+            string publickey = rsa.ToXmlString(false);
+            string privatekey = rsa.ToXmlString(true);
+
+            // 要加密的明文
+            string plain = Base32Encode(RandomNumberGenerator.GetBytes(10));
+
+            // 加密明文，获得密文
+            string secret = Encryption.RSAEncrypt(plain, publickey);
+
+            // 保存密文到文件
+            File.WriteAllText(publicpath, secret);
+
+            // 保存私钥到文件
+            File.WriteAllText(privatepath, privatekey);
+        }
+
+        /// <summary>
+        /// 生成随机秘钥字符串
+        /// </summary>
+        /// <param name="data"></param>
+        /// <returns></returns>
+        private static string Base32Encode(byte[] data)
+        {
+            const string alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
+            StringBuilder result = new((data.Length * 8 + 4) / 5);
+            int buffer = data[0];
+            int next = 1;
+            int bitsLeft = 8;
+            while (bitsLeft > 0 || next < data.Length)
+            {
+                if (bitsLeft < 5)
+                {
+                    if (next < data.Length)
+                    {
+                        buffer <<= 8;
+                        buffer |= data[next++] & 0xFF;
+                        bitsLeft += 8;
+                    }
+                    else
+                    {
+                        int pad = 5 - bitsLeft;
+                        buffer <<= pad;
+                        bitsLeft += pad;
+                    }
+                }
+                int index = 0x1F & (buffer >> (bitsLeft - 5));
+                bitsLeft -= 5;
+                result.Append(alphabet[index]);
+            }
+            return result.ToString();
+        }
+
+        /// <summary>
+        /// 生成基于当前时间戳的6位数字2FA验证码
+        /// </summary>
+        /// <param name="secretKey"></param>
+        /// <returns></returns>
+        public static string GenerateCode(string secretKey)
+        {
+            byte[] key = Base32Decode(secretKey);
+            long counter = GetCurrentCounter();
+            byte[] counterBytes = BitConverter.GetBytes(counter);
+            if (BitConverter.IsLittleEndian)
+            {
+                Array.Reverse(counterBytes);
+            }
+            HMACSHA1 hmac = new(key);
+            byte[] hash = hmac.ComputeHash(counterBytes);
+            int offset = hash[^1] & 0x0F;
+            int code = ((hash[offset] & 0x7F) << 24 |
+                        (hash[offset + 1] & 0xFF) << 16 |
+                        (hash[offset + 2] & 0xFF) << 8 |
+                        (hash[offset + 3] & 0xFF)) % (int)Math.Pow(10, DIGITS);
+            return code.ToString().PadLeft(DIGITS, '0');
+        }
+
+        /// <summary>
+        /// 获取当前时间节点
+        /// </summary>
+        /// <returns></returns>
+        private static long GetCurrentCounter()
+        {
+            TimeSpan timeSpan = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+            return (long)(timeSpan.TotalSeconds / INTERVAL_SECONDS);
+        }
+
+        /// <summary>
+        /// 生成验证码
+        /// </summary>
+        /// <param name="input"></param>
+        /// <returns></returns>
+        /// <exception cref="ArgumentException"></exception>
+        private static byte[] Base32Decode(string input)
+        {
+            const string alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
+            int length = input.Length;
+            int bitsLeft = 0;
+            int buffer = 0;
+            int next = 0;
+            byte[] result = new byte[length * 5 / 8];
+            foreach (char c in input)
+            {
+                int value = alphabet.IndexOf(c);
+                if (value < 0)
+                {
+                    throw new ArgumentException("Invalid base32 character: " + c);
+                }
+                buffer <<= 5;
+                buffer |= value & 0x1F;
+                bitsLeft += 5;
+                if (bitsLeft >= 8)
+                {
+                    result[next++] = (byte)(buffer >> (bitsLeft - 8));
+                    bitsLeft -= 8;
+                }
+            }
+            return result;
+        }
+    }
+}