Jim, any consideration to setting up your own website on which clients can securely (via https) submit documents and comments to you, and perhaps receive replies back in the same way? The only issues then would be keeping your server secure (encrypted filesystem, perhaps), and of course ensuring that the client doesn't have some sort of spyware on his own machine.
Well, we're getting off the topic of IP law and more into attorney-client privilege and computer security. So, my thoughts on the topic aren't really based on any sort of expertise in the area(s).
There are two levels of security to be concerned about: (i) maintaining a reasonable expectation of privacy sufficient to avoid waiver of privilege and (ii) keeping important secrets from being accessed in fact. I've already addressed the first for e-mail, and I don't see why a secure web connection (https, secure authentication, VPN, etc.) would be any different.
As for the second level of security, I'm not sure what to say. I guess I take some comfort in that there are much more attractive targets out there than patent practitioners' client-confidential information -- though, we'd be relatively high up the list given how some segments of the software community feel about patents. In the wake of more sensitive data repositories (thinking primarily of defense, government, and corporate systems), many very good tools trickle down to us. So, typical tools for HTTPS, VPNs, and such are pretty good, from what I understand.
I tend to use Knoppix or another Linux LiveCD, freshly rebooted to be sure nothing was hiding in memory, whenever I have to submit credit-card, SSN, or other information commonly stolen for fraud purposes. That way, although the vendor might get compromised, at least I know *my* machine isn't going to burn me.
Hmmm.... I'm not sure where you would keep all your electronic files or at least works in progress. My stuff is way too large to fit on a thumb drive. And, my preference is for the reliability of RAID systems which tend to be too big for any temporary connection to a clean system every day.
One thing I would suggest most people avoid is sole reliance on out-of-the-box Microsoft tools -- operating systems, server systems, etc. I have 2 reasons to make this suggestion.
First, MSFT is the largest install base and most crackers focus on cracking those systems.
Second, Windows grew up from DOS, so much of the multi-user and security aspects (and GUI as well) were sort of retro-fitted on top -- not unlike building a secure military bunker by building on to a wooden fort built by 12-year-olds some 30 years ago. Yes, I understand that all versions of Windows are now based on NT rather than DOS (last DOS descendant was WinME), but, if DOS is a mere babe and Unix is an adult, NT is like an adolescent. At the very least, I still get the impression that MSFT is building computers for grandmothers to e-mail/chat with the grandkids and trying to stick enough seriousness into the OS that the computers can be used for business too.
If all your computing leaves absolutely no trace, I'd say your system/approach is over-kill. But, that's just one person's opinion. And, I think there is little doubt that leaving no trace is at least adequate. The only more digitally secure is not using a computer at all.
Regards.