I see two seperate aspectes:
+ there are several providers for credit card transactions thru the iPhone/iPad with iApps using digital signatures. Though they concider theirs digital signatures as proofed and valid in court. Parcel-Services also use digital gadgets for signatures.
ought to know about that issue. Maybe it's possible to do some research about how-they-do-it.
- you might need to proof in court that yours solution can't copy/paste any signatures. I would not know how to do that since as the developer, you can those settings at will
= most of the credit card apps have a send-receipt-to-customer per Email function (as a pdf with the signature in it). Using this to deal with yours legal issue in yours case would only work if customer confirms the receive of Email and therefor accepts the service-agreement
Is the signature for goods received or to be delivered or part of a contract, etc. There are many different conditions for the signature to be given.
The easiest is this, maybe. Is the customer placing their order on their own computer or iPad rather than yours? If so, you're half way there since you can now with 12 easily capture the unique id of the computer (or the NIC) and the ip address etc and use that to show they used their computer...
Now the issue would be whether one or both of you are lying cheating swindlers, ahem...
If you are dealing with thousands, 10s of thousands or more in dollars, you should use a provable paper invoice or set up something like paypal where the customer pays up front rather than just signs.
I guess the issue is what kind of sale you are making and whether or not you can trust your customer.
One backup method is to send an email asking for confirmation before you deliver anything and certainly make sure every customer knows this will happen and that it is for their protection (nice advertising).
And, talk to a lawyer if you are talking serious dollars in sales.
If you are worried about losing $10 every now and then, why worry about it so much.
Rereading, if your clients are trying to bind someone to a contract for service agreements and they are truely legitimate, they would want to add a clause allowing cancellation within 25/36 hours of receiving an email about the agreement to prove they are legitimate, not high pressure sales and to protect themselves from evil lying salesmen who will fake a contract to get a comission...
So I think your project should be not to just make a buck but to protect your client and their client with a failsafe order system that protects everyone (including you).
I've done a lot of sales and never had a cancellation because I was super honest with the buyer and gave them a dozen chances to backout before they signed. I've seen cancellations where high pressure salesmen got a signature and then the client canceled. In fact when I bought my last car the finance manager really pressured me to buy their high priced do nothing repair insurance and the only way I could get the car was sign the contract after reading it and seeing there was a cancellation clause and I followed it to the letter when I canceled the insurance. I had my ownl.
So I think the question is not whether the signature is legal but whether the sale is legit and I would design the system to insure that it was.
I realize that people with out much sales experience would miss this distinction and its hard to see the parts of the puzzle in the heat of battle.
Efficient & Jack,
Appreciate your responses, very fair point about the amount of money, and moreso worrying about the legit sales, unfortunately when some people sign an agreement then realise 6 months on they're up for a large bill (all legit and 99% of their customers dont complain and pay because they were expecting it) some people still complain
Currently i'm just setting up whenever you enter a signature field, it loads a menu set that does not allow copy/paste, and re loads the normal menu set on field exit
Also Removing all rights to add or delete or modify records if ANY signatures have fields in them
At the moment i'm hoping this should cover all grounds, however i still think its a very interesting topic!
When it comes to "locking" a record so that it can't be edited...
See "Editing record access privileges" in FileMaker Help and check out this particular sub section: "Entering a formula for limiting access on a record-by-record basis".