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Author Topic: signature capture questions  (Read 2541 times)

cwtart

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signature capture questions
« on: August 06, 2013, 04:49:38 AM »
I am planning on adding signature capture to my web app and have some questions.

1. The NetTalk sample app (example 75) stores the signature in a 64k memo field and also creates a .bmp file of the image. In the real world, why create a .bmp at all and not just store as a string - then create the image file when needed?

2. when storing the signature as a string - what is rule of thumb for string size, if any? Is a 64k memo field overkill or necessary?

3. I am concerned about storing image files as a blob in a .tps file - the file size limits of 2g could be reached quickly in some applications.

4. what about storing each image file as a separate file? I do this in other areas but am concerned with the legal integrity of a signature. Does anyone have any guidelines to make a stored signature image file secure and legal? Can the signature be stored separately or does it need to be embedded in the document that it applies to?

Thanks,

Chuck

Bruce

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Re: signature capture questions
« Reply #1 on: August 06, 2013, 10:41:20 PM »
Hi Chuck,

>> 1. The NetTalk sample app (example 75) stores the signature in a 64k memo field and also creates a .bmp file of the image. In the real world, why create a .bmp at all and not just store as a string - then create the image file when needed?

Of course the example is just an example. So you can create the BMP from the string anytime you like. You don't need it to recreate the signature on the form (ie inside the Signature field type) but you will need it to display the image of the signature in other places - like on browses.

>> 2. when storing the signature as a string - what is rule of thumb for string size, if any? Is a 64k memo field overkill or necessary?

it depends completely on the complexity of the signature. So I guess you would need to capture a bunch of signatures to answer that question.

>> 3. I am concerned about storing image files as a blob in a .tps file - the file size limits of 2g could be reached quickly in some applications.

sure. Feel free to store it somewhere else.

>> 4. what about storing each image file as a separate file? I do this in other areas but am concerned with the legal integrity of a signature. Does anyone have any guidelines to make a stored signature image file secure and legal? Can the signature be stored
separately or does it need to be embedded in the document that it applies to?

That's outside the realm of my expertise. Obviously the signature is digital, so it can be digitally manipulated. I'd use it for deliveries and things like that. I'd be less inclined to use it on multi-million $ contracts....

"Digital Signing" of documents is something quite different, using Certificates and Private Keys and so on.

Cheers
Bruce