Generate Token C#

Token.cs

var bytes = new byte[40]; // byte size
using (var crypto = new RNGCryptoServiceProvider())
  crypto.GetBytes(bytes);

var base64 = Convert.ToBase64String(bytes);
Console.WriteLine(base64);

// Prepend with a Guid:
var result = Guid.NewGuid().ToString("N") + Convert.ToBase64String(bytes);
Console.WriteLine(result);

// Alphanumeric string:
result = Regex.Replace(result,"[^A-Za-z0-9]","");
Console.WriteLine(result);