1
$\begingroup$

I have gigabites of files, which I have to backup. I have some servers for storing this files. But these servers are untrusted. So I need to encrypt files, then backup files. When my PC breaks down, I will dowload files from unstrucsted servers and restore them.

So, basically, I think about AES-256. Is it OK for me, or there is more suitable symmetric algorithms?

Improve this question
$\endgroup$
1
  • 1
    $\begingroup$ There is much more you have to worry about than a choice of pseudorandom permutation family, which is what AES-256 is—that's about the least interesting question. At the very least, start one level up: What authneticated cipher should I use? Standard answers are NaCl crypto_secretbox_xsalsa20poly1305, AES-GCM, AES-SIV. (These are all somewhat different: slightly different security contracts. If you want details on that, ask another question!) Study the design of Tarsnap or borgbackup if you're interested in actually pursuing this. $\endgroup$
    – Squeamish Ossifrage
    Commented Jun 12, 2018 at 0:46

1 Answer 1

Reset to default
1
$\begingroup$

Just a note: AES is not a encryption scheme, it is technically just a block cipher; though it is a fine one.

To create a cipher you need to use it in a mode like counter mode.

To obtain chosen ciphetext security (which is the usual aim) you should use an authenticated encryption scheme such as Galois/Counter Mode.

As usual, don't try make it yourself, use a premade secure library.

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.