I have several dar archives created some years ago, using the late-lamented kdar (now obsolete.) and all were created with passwords..

I recently came to extract one, but found to my dismay that the latest (2.4.x) version of dar was unable to do this, and failed with the following error message:
“FATAL error, aborting operation
Current implementation of blowfish encryption is not compatible with old (weak) implementation, use dar-2.3.x software (or other software based on libdar-4.4.x) to read this archive”

To say that this was disappointing, would be an understatement…    After all, isn’t the whole point of archives that they should be able to be recovered later in time??

Fortunately, the solution (at least for the time being) is to deinstall dar-2.4.x and install dar-2.3.x (which was available up to Fedora 18..)..
But – of course – if I want to create a new archive, then I should really be using dar-2.4.x….    So, I am faced with the messy solution of having two dar versions (and their associated libraries) installed, to be able to do this…

A better solution would be to have dar-2.4.x able to extract old archives using the ‘old/unsafe’ blowfish, but always use the ‘new/improved’ blowfish for creating new ones..

In a perverse way, this lack of backward-compatibility creates an extra level of security, as it make the older passworded archives impossible to open – at all – with the current software!

Robert Gadsdon,  September 30, 2013.