[SOLVED] How to split encrypted files for long-term storage on DVDs?

[Alexllte]

I'm not sure if this question belongs in the “hardware category,” but I can’t find anywhere else to ask, so here it goes.


My computer was hit with ransomware last year, and I have video files that have been encrypted (via RSA and AES-128).

I know the possibility of decrypting it is slim, but the best solution I can think of other than deleting them is to leave it in long-term storage.

I’m currently interested in buying write-once disc drives and saving them, but each disc only has 4.7GB of storage.

So my guess is to bundle the video with 7z or WinRAR and split the archive into parts and store them on each disc.

I don’t know if this is a practical solution, and I’m aware I cannot alter the files (I have to use lossless compression) else they can’t be decrypted.



Is this a good idea? Are there better solutions?

 

[Grobe]

You can do that. You can do either 7z or rar

Also, I suggest you put a sha256 (or similar) checksum file for each of the splitted rar/7z files so you can verify their integrity later on.

I beleive Winrar is able to create a checksum file, so that if one of the parts files goes corrupted, you can still save the contents of the archive.

 

[USAFRet]

Also, be wary of the DVD concept.
Unless you buy the ($$) archival quality, they my not last.

I have some I burned with movies from 5-10 years ago. I'm getting maybe a 50% success rate in reading them.

 

[fzabkar]

Use "Store" mode in 7Zip. This does not compress the file. In any case video files are already compressed.

BTW, many ransomware variants already have free decrypters. Do you know the name of the malware?

 

[Alexllte]

Use "Store" mode in 7Zip. This does not compress the file. In any case video files are already compressed.

BTW, many ransomware variants already have free decrypters. Do you know the name of the malware?

It's a new variant of Dharma.
It brute forces RDP connections, and a human operator steals passwords on the local machine (I still have the .dat file) then runs the virus.
The master key of the previous variant has been released on beepingcomputer forums, but not this variant.