This project has moved. For the latest updates, please go here.

Compression

Topics: Feature Requests
Dec 12, 2014 at 11:59 AM
AS VeraCrypt's driver is in a unique low level position I wondered if it would be possible to offer the user compression ?

I understand compressing data before encryption helps to frustrate cryptanalysis, so if correct, this adds further security.

Compression would also provide a useful added benefit to users. It would allow them to make smaller containers and greatly improve the capacity on USB flash drives etc.

How it would work...

When the user creates a new volume they will be offered to make an encrypted volume and also an encrypted + compressed volume.

If the user selects compression the volume created will automatically and transparently compress data written to it.

I have done some limited research and found 7zip is probably best to use. Not only does it offer better compression ratio's than most other compressors, but it has an open and free licence.

I believe this would be a very useful feature to add. Although not a 100% security feature (apart from potentially frustrating analysis) it would allow the creation of much smaller volumes. This would help the user in general, but also allow for faster overwriting of volumes in an emergency due to their smaller size.

Thanks.
Coordinator
Dec 12, 2014 at 10:40 PM
I don't think it is possible to implement compression in the case of disk encryption because we need to be able to access the data at any position with a data unit equal to the hard drive sector size.

if there is compression, in order to decompress a block, we certainly need to decrypt and decompress a lot of data which will degrade performance badly.
Dec 13, 2014 at 12:12 PM
OK I understand ... I think :)

Thank you for the reply. We need a section where we can list rejected requests so others don't ask the same questions again.