Using Bitmap's for captchas

[gomzi]

Hi,
I would like to know whether it is safe to use images created using bitmap class available in .net for captchas?
Also, when many people access the site at the same time, will there be any problem?
And lastly, in case you feel that it is not safe to use bitmap class for this purpose, could you kindly tell me as to what the rest of the world out there uses?

Thanks,
Gomzi.

[Plater]

What is a "captchas"?

If you are refering to the bitmap object and creating your images in code, I would say that there is a performance hit but without knowing anything else, probably not a security risk

[gomzi]

What is a "captchas"?

If you are refering to the bitmap object and creating your images in code, I would say that there is a performance hit but without knowing anything else, probably not a security risk

Thanks Plater.

Captcha - The images that we see on webpages (word verification) for telling computers and humans apart.

i.e. I wish to know whether it is thread safe?

Thanks,
Gomzi.