Unsure it's the best place to ask, anyway:

I know symmetric encryption is the best for such tasks but I am planning to encrypt large backup files (between 10 and 100GB) with my private PGP key. My purpose here is to use several layers of encryption, each of them using a different algorithm to prevent 0day exploits on a specific algorithm. So you get me: AES first then RSA.

I have just tried to perform the above and while there is absolutely no problem with AES (takes about 20min on my file just using 7zip), PGP (using gpg4win / kleopatra) is taking a while until a time out message stops the process after more than 30min (I wasn't timing maybe it was an hour or two).

I have read there is no specific limit to file size for PGP encryption or it may be related to your memory size but nothing clear. Would you have more information about this?


  • $\begingroup$ AES then ChaCha20? $\endgroup$ – kelalaka Feb 27 at 8:42
  • $\begingroup$ It’s not that I don’t trust AES actually but rather the way a software would use it to encrypt, the way it’s implemented. For example Truecrypt could be known by some for having a valid exploit (there’s always a debate about this for years or even a backdoor and no one will ever know unless some kind of Wikileaks happens again. I was thinking mixing symmetric and asymmetric would be relevant if I need to encrypt twice. $\endgroup$ – Ozwel Feb 27 at 8:54
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    $\begingroup$ Truecrypt? That is very old and AFAIK nobody uses that. Bugs/exploits always can be found the point is how fast they are patched. Use Veracrypt like this way $\endgroup$ – kelalaka Feb 27 at 8:58
  • $\begingroup$ I agree I’ll certainly have to think differently and go for another option. But whatever happens I’ll still be interested in know about PGP limitations :) thanks for the link btw. $\endgroup$ – Ozwel Feb 27 at 9:06
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    $\begingroup$ There are several encryption modes that PGP can use; you'd have to specify which one you are using for us to indicate the maximum size. However, a good program should not "hang" even if you exceeded that limit. It would either have to 1. exit early 2. crash or 3. keep going (in the order of preference). This is more likely a limit within the program; for those kind of questions Super User is a better place. $\endgroup$ – Maarten Bodewes Feb 27 at 11:13

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