How do you create a form with a graphic security entry?

Discussion in 'ASP General' started by Larry Bud, Feb 23, 2006.

  1. Larry Bud

    Larry Bud Guest

    Ok, I don't know what they're called, but you know the form: The page
    displays a "code", usually on a similar color background (dark gray),
    and the text is all squiggly.

    It's an attempt to foil the bots that go out and process forms. The
    user has to type in the code they see, when the graphic itself should
    be unreadable by character recognition engines.

    So, how are the graphics generated, and how do you implement this?

    Any links to resources would be appreciated. It's hard to find any
    articles when I don't know what to call it!
    Larry Bud, Feb 23, 2006
    #1
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  2. Larry Bud

    McKirahan Guest

    "Larry Bud" <> wrote in message
    news:...
    > Ok, I don't know what they're called, but you know the form: The page
    > displays a "code", usually on a similar color background (dark gray),
    > and the text is all squiggly.
    >
    > It's an attempt to foil the bots that go out and process forms. The
    > user has to type in the code they see, when the graphic itself should
    > be unreadable by character recognition engines.
    >
    > So, how are the graphics generated, and how do you implement this?
    >
    > Any links to resources would be appreciated. It's hard to find any
    > articles when I don't know what to call it!
    >



    What is the word verification option?
    http://help.blogger.com/bin/answer.py?answer=1203

    How to Spoof-proof Your Logins
    http://www.devx.com/dotnet/article/21308/
    McKirahan, Feb 23, 2006
    #2
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  3. Larry Bud

    Lee Carnell Guest

    "Larry Bud" <> wrote in message
    news:...
    > Ok, I don't know what they're called, but you know the form: The page
    > displays a "code", usually on a similar color background (dark gray),
    > and the text is all squiggly.
    >
    > It's an attempt to foil the bots that go out and process forms. The
    > user has to type in the code they see, when the graphic itself should
    > be unreadable by character recognition engines.
    >
    > So, how are the graphics generated, and how do you implement this?
    >
    > Any links to resources would be appreciated. It's hard to find any
    > articles when I don't know what to call it!
    >


    When I wrote one of these modules a few years back I used ASPImage to create the
    graphic - My code created a random number which was then 'fused' (using
    ASPImage) onto an existing background image and saving it under a different name
    (I used the Session id for the graphic name).

    Next the random number is encrypted using SHA256.

    The registration form presents the graphic plus an entry field to re-type the
    numbers and the encrypted random number is passed in the form via a hidden
    field.

    On the form processing page the user entered number is encrypted and that string
    is evaluated against the value passed via the form. There are other various
    checks carried out on the other data entered from the registration form.

    YMMV

    Lee
    Lee Carnell, Feb 24, 2006
    #3
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