Integrity of forms

[Nicholas Bohm]

One often has to fill in forms.  This can be tricky with a wordprocessor,
and one is often reduced to the retrograde step doing it by hand, when one
might like to advance progressively to doing it by email.

The advantage to the recipient of the use of the printed form is its
integrity:  they can see that their own text is unaltered.  If the user
scanned the form into text and used a wordprocessor or email, the recipient
would have to check the received form to ensure that there had been no
accidental or deliberate changes which altered its effect.

An example would be a printed form of guarantee required by a bank.  A
guarantor who slipped an undetected "not" into a guarantee might reduce its
worth to the bank quite considerably.

A conventional digital signature would secure the integrity of the
uncompleted form, but would be destroyed by the insertions properly made by
the person completing it.  It would of course be different if the
insertions constituted a separate "layer".

Has anyone come across the use of cryptography to assure the integrity of a
form for completion in this way?  It could be a quite widespread e-commerce
requirement.

Regards,

Nicholas Bohm

Salkyns, Great Canfield,
Takeley, Bishop's Stortford CM22 6SX, UK

Phone		01279 871272	(+44 1279 871272)
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