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Showing posts from September, 2020

Human Captcha (Not Robot) React Component with .Net Core WebApi Backend

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A captcha is a challenge response test to determine whether or not the user is human. We may create a React human captcha component with a .Net Core Web API back-end.  Back-end Our back-end is ASP.Net Core Web API 3.1. Back-end will generate a truly random alpha-numeric captcha value, creates a binary image using System.Drawing namespace. Back-end will verify the user input value against the generated value and  return an authentication Token to be used in Forms. The method that generates a random captcha value and creates a binary image is as follows:         /// <summary>         /// generate captcha image         /// </summary>         /// <param name="size">alphanumeric length of the captcha</param>         /// <returns>image properties and image binary data</returns>         private async Task<CaptchaImage> generateCaptcha(int size)         {             try             {                 int width = size * 30;                 int