Simple Captcha

Question

User746671234 posted

Hi, does anyone knows simple captcha for asp.net.  I found many in google but most of them are not working on live server.

I need simple captcha.

Answer 1

User-491950272 posted

Greetings,

You can use Google Captcha V2. First get the captcha and they will give you a div element, put this at the required place and now send a web request to the web client as:

public bool Verify(string encodedResponse)
        {
            var client = new WebClient();

            string privateKey = "{put here your private key}";

            var GoogleReply = client.DownloadString(string.Format("{put here your verification URL}", privateKey, encodedResponse));

            return JsonConvert.DeserializeObject<CaptchaResponse>(GoogleReply).Success; //De-Serialize the JSON to CaptchaResponse.cs Model

        }

Here is the CaptchaReponse.cs class as:

public class CaptchaResponse
    {
        [JsonProperty("success")]
        public bool Success { get; set; }

        [JsonProperty("error-codes")]
        public List<string> ErrorCodes { get; set; }
    }

The based upon this Success serialized object you can determined that whether the captcha is valid or not. The reponse that you get from the Google is in JSON format.

Answer 2

User36583972 posted

Hi  ravininave,

I found some examples in the below for your reference.

Simple Captcha with ASP.Net :

http://www.c-sharpcorner.com/article/simple-captcha-with-Asp-Net/

How to implement simple Captcha in ASP.Net:

http://www.dotnetawesome.com/2014/07/how-to-implement-simple-captcha-in-aspnet.html

How to implement Captcha in ASP.Net:

http://www.aspsnippets.com/Articles/How-to-implement-Captcha-in-ASP.Net.aspx

Best Regards,

Yohann Lu