I'm looking to protect sensitive data from deletion by hosting it on Amazon Glacier.

I'd like to secure that data against possible hacks of Amazon by encrypting it, and I'd like for the data to be secure even if vulnerabilities are found in one of the algorithms that I'm using.

I'm thinking of encrypting the data with AES Crypt, since it has a good reputation. I'm also thinking about adding 1-2 additional layers of security.

Can anyone recommend some other reputable encryption utilities to go together with AES Crypt for this purpose?


You could also use asymmetric crypto to further encrypt this data. So you could encrypt it with RSA, but note that since you have to use padding with RSA to encrypt the data properly, padding would significantly increase the filesize. For example, OAEP (Optimal Assymetric Encoding Pattern - https://en.wikipedia.org/wiki/Optimal_asymmetric_encryption_padding) will more than double your filesize.

Other asymmetric crypto alternatives you can look at: Diffie Hellman, Paillier Cryptography

Another common symmetric crypto algorithm is Serpent

But be aware, when you encrypt something twice, the strength of the encryption doesn't add together (i.e. two 256 bit encryptions with seperate keys does not give it 512 bit security. Due to Meet in the Middle attacks, it actually ends up with ~ 257 bits of security instead.)

Also be sure your using AES with a secure block chaining mechanism, such as https://en.wikipedia.org/wiki/Galois/Counter_Mode .

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    $\begingroup$ I'm not sure you should recommend DH or Paillier without further qualification. How will they enhance the security for Arsen? Blowfish should not be recommended anymore, mainly because the author doesn't recommend it anymore. The only time it could be included is when it is the only (relatively) secure option available and the mode of operation doesn't require a 128 bit block cipher. $\endgroup$ – Maarten Bodewes Jul 9 '17 at 9:49
  • $\begingroup$ I didn't realize blowfish was outdated, because I solely use AES for symmetric crypto now, thanks for pointing that out. Arsen in the question pointed out that he was looking for a secondary cryptosystem to use in the event that AES is broken. I'm not sure what qualification is needed on DH and Paillier, presuming he sets them up according to standards. $\endgroup$ – Ninja_Coder Jul 9 '17 at 13:37
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    $\begingroup$ Using asymmetric crypto in this scenario makes no sense whatsoever. Regardless of it being redundant (in Arsen's context), it's also inefficient. A modern alternative to AES would be Chacha20 or XSalsa20. @Ninja_Coder snaps for mentioning Meet in the Middle attacks $\endgroup$ – hunter Jul 9 '17 at 13:41
  • $\begingroup$ This question is basically Arson asking what other methods he can use for redundancy though. "I'd like for the data to be secure even if vulnerabilities are found in one of the algorithms that I'm using." Your right though, Chacha20 would be a much better choice than asymetric crypto, especially considering its upcoming inclusion in TLS $\endgroup$ – Ninja_Coder Jul 9 '17 at 13:47

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