Yes this is possible.
I use an active directory web service to identify my users and then also
check their group memberships and base what they see or can modify on that.
You could also verify their identity by just hardcoding their username or
name or other means into the form.
Then you can just use conditional formatting to make a section or control
readonly or hidden if the current user is not the intended user.

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Clay Fox / Microsoft InfoPath MVP
www.InfoPathDev.com / The InfoPath Authority / Downloads, Samples, How-To,
Experts, Forum
> Hello all,
>
[quoted text clipped - 11 lines]
> Thank you in advance,
> Hrvoje
Hrvoje Vrbanc - 09 May 2008 11:37 GMT
Hi Clay!
Thank you for the reply. It works fine.
> Yes this is possible.
>
[quoted text clipped - 26 lines]
>> Thank you in advance,
>> Hrvoje