Encrypt file while you are using it

[Bart Silverstrim]

Manuel Gomez wrote:
> Hi, i would like to maintain encrypt an archive in all moment, so i
> would like to know what software can be this.
> 
> Now i am using Truecrypt, but when i mount the encrypted directory it's
> vulnerable. I want to mount the file and that the file can remains
> encrypt.
> 
> Somebody can help me?

In order to use an encrypted file or volume, it must be decrypted while 
in use, as you've already observed. Funny enough I was just reading 
about OS X's filevault and changes made between 10.4 and 10.5 to address 
this type of issue a little further...part of it is that if the user is 
logged in and the laptop is stolen, encryption won't help unless the 
password at wake and password from screensaver are set.

There's no way I've ever seen to have a file encrypted AND used at the 
same time by the user. This is the whole reason non-encrypted swapfiles, 
state of memory, and temp files are a vulnerability in a protection 
scheme. Encrypted files must be in an unencrypted state to be used.