Encrypted zip files

[Castor]

I use encrypted zip files (.zipx, password protected) which contains many files that I work on regularly. The file is approximately 50 MB in size. If I use bittorrent, will the entire file be synced (uploaded/downloaded) whenever I make any change?

 

Bandwidth is an issue to me, so it would help me immensly if only the changed parts of the file is synced.

[GreatMarko]

Please read the Unofficial FAQ, particularly the section "When a file changes, does Sync transfer the entire file again, or just the part that's changed?"

[nils]

It depends on your zip file implementation and how changes are being saved/how the file changes after you encrypt it again.

 

I would recommend EncFS, which does pretty much what you want (encryption) but every file is encrypted on its own, making it nice and easy for btsync to see which file was changed. Although it could then still be the same issue, because every file gets encrypted, theoretically changing the whole file depending on how EncFS does it internally. One benefit though: it would do so atomically for each file, and reduce any overhead in the worst case.

[Castor]

Thanks for the reply. I read somewhere that an encrypted zip file will change the entire contents on every save, though I am not sure.

 

The reason i am using Winzip (.zipx files) is because they can encrypt my files and I use winzip at my work as well. If I use EncFs, I guess I should save the original contents (unencrypted) in a different folder, which is not secure.

 

Do you know of any encrypted software which is secure as well as portable, and can also sync with bittorent sync without uploading entire file everytime?

[ThaumaTechnician]

TrueCrypt will do the job.  If you create a, say, 100GB container, the entire container isn't rewritten when you update one byte on one file.  Just a small section of the container file (in this case 64KB, if memory serves).

 

Truecrypt is superb software.  (And, if I may be allowed a dig, they release all of their encryption specs.  Heck, they even release the source code....)