using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Security.Cryptography;

    class Security
    {
        //生成哈希密码
        public static string HashingPassword(string password)
        {
            byte[] salt;
            new RNGCryptoServiceProvider().GetBytes(salt = new byte[16]);
            var pbkdf2 = new Rfc2898DeriveBytes(password, salt, 10000);
            byte[] hash = pbkdf2.GetBytes(20);
            byte[] hashBytes = new byte[36];
            Array.Copy(salt, 0, hashBytes, 0, 16);
            Array.Copy(hash, 0, hashBytes, 16, 20);
            string passwordHashed = Convert.ToBase64String(hashBytes);
            return passwordHashed;
        }
        //密码验证
        public static bool PasswordMatch(string enteredPass, string hashedPass)
        {
            byte[] hashBytes = Convert.FromBase64String(hashedPass);
            byte[] salt = new byte[16];
            Array.Copy(hashBytes, 0, salt, 0, 16);
            var pbkdf2 = new Rfc2898DeriveBytes(enteredPass, salt, 10000);
            byte[] hash = pbkdf2.GetBytes(20);
            for (int i = 0; i < 20; i++)
            {
                if (hashBytes[i + 16] != hash[i])
                {
                    return false;
                }
            }
            return true;
        }
        //生成随机密码
        public static string RandomPassword()
        {
            int length = 12;
            const string valid = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
            StringBuilder res = new StringBuilder();
            using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider())
            {
                byte[] uintBuffer = new byte[sizeof(uint)];

                while (length-- > 0)
                {
                    rng.GetBytes(uintBuffer);
                    uint num = BitConverter.ToUInt32(uintBuffer, 0);
                    res.Append(valid[(int)(num % (uint)valid.Length)]);
                }
            }
            return res.ToString();
        }
    }