shakenbake, what about deleted emails when I'm receiving them from work, can they also be retrieved and read? I'm working on a local LAN
If your work is running an enterprise class Email server (i.e. Microsoft Exchange, Lotus Notes), the Email server can be configured to keep every email in-to, out-of or even deleted emails for whatever retention period configured. The idea is, for example, if company mgmt needs to go back in time to review threads regarding a customer sale, they can see everything. Even if Emails were deleted by the user. We have our server set-up to retain and archive for 1 year - it really only costs disk space which is relatively cheap.
The retention period for online email services (Google, Hotmail, Bell, Rogers, etc.) isn't public information, but I've been told by people who would know that it's ~60 days on the servers and back-ups are kept for 90-120 days.
Same holds true for most corporate and Internet based Instant messaging (IM) services.
Last tidbits,
- Unless the email and IM servers employ an encrypted database, anyone with access to the server or application can read your messages. In theory only authorized IT staff can access the servers, but that doesn't guarantee they are 100% trustworthy. If the database is encrypted, only staff with the privileged passwords will be able to un-encrypt user emails. It takes allot of CPU power to securely encrypt 100s or 1000s of emails a second, so not surprisingly many companies don't run encrypted databases.
- Even when an email is deleted, the actual file on a hard drive is not immediately deleted, the sector(s) it occupies are simply marked as available. It could take a few minutes to possibly weeks before the sectors are overwritten thus destroying the original content - it depends on how heavily utilized the drive/storage pool is used. That's why it's possible to recover deleted files.
- If a drive is replaced (perhaps because it's too small), a good IT shop will use a Mil-Spec program to overwrite the drive several times with a specific sequence of 1s and 0s in a random order. Not all IT shops are good and as a result your private data could be compromised
- If a drive fails, it's possible it's just the interface or only a handful of sectors on the drive platters, thus leaving a large percentage of the content intact. It's also possible certain failures prevent a proper erasing of the drive. A good IT shop will physically destroy the drive, but some do end up in the trash with your private data intact.
- Lastly, the email you sent is received by someone. No guarantee that person's PC is 100% secure or they could forward it to someone else without your knowledge or permission. Ask Hillary ......
Bottom line: treat ALL of your electronic communications as insecure and never put anything in writing that would compromise you.