If you want to make interception more difficult, use an SSL connection. Then it will at least be sent encrypted.
Or let those doctors e-mail it to you directly, without using the webpage.
pritaeas
Posting Expert
5,484 posts since Jul 2006
Reputation Points: 653
Solved Threads: 875
Imo, CAPTCHA will not serve your purpose much. SSL is the best way. Find it expensive? I guess if so, there's the alternative of making your own SSL (but then users viewing a warning may be a downside).
reganstar
Junior Poster in Training
69 posts since Apr 2009
Reputation Points: 10
Solved Threads: 10
Capthcha is used to avoid spam generated by bots, it can not defeat or restrict a human.
urtrivedi
Nearly a Posting Virtuoso
1,306 posts since Dec 2008
Reputation Points: 257
Solved Threads: 270