Write-protecting a usb stick

[paul1149]

Hi,

I'm interested in write-protecting a usb stick. I would like full access when it's on my machine and I'm logged in, but in other machines I would like a log in dialog to qualify the user trying to write to the stick. If he is able to sign in, he then would be able to write.

My idea was to convert the stick to NTFS, and thus gain the ability to set permissions, and to set them to only myself and the super admin. I think that will work regarding keeping the stick open on my machine and closed on anyone else's, but on another machine would a log-in screen arise, or would the stick strictly be unwritable?

Or is my scheme flawed in some other way?

Thanks,
p.

 

[paul1149]

I just experimented with a small stick. The method allows writing on my own machine under my own account, but it flatly blocks access on my XP machine, with no opportunity to log in for access.

I could designate one folder to be writable to everyone, but that would defeat the purpose, to some degree anyway, of securing the stick against viruses.

 

[brady]

Those NTFS permissions you are setting are S-I-D specific and won't work on another machine (unless you're in a domain environment).

Only way I can think to do what you're asking, is to encrypt the drive with TruCrypt or similiar. It will then prompt for secure disk password and that can be used anywhere/anytime.

 

[paul1149]

Hi brady,

I'm not quite following what you're saying. Are not NTFS permissions held in the filesystem's owwn alternate data stream, and is that not why XP respected Win7's settings? (I'm on a workgroup, not a domain.) Of course, XP doesn't have 7's granularity, so I guess I can't expect other than a plain access denied. And I have no way of testing the stick on an alternate 7 box at the moment.

TrueCrypt sounds like an interesting solution. I had thought of it but preferred to use an organic solution, but maybe I need to consider it further.

Thanks,
p.