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I'd like to know if Aescrypt is a valid tool, or if for a very secure protection, the only choice is to use a software like gpg, or similar.

More I've another curiosity, if one doesn't want to use encrypted email with a related software, could it be secure send AES encrypted files, through normal email connection ? Could it be usefull to use a rar AES protected archive, to further protect files ?

Thanks

webose
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See this question for some caveats. There is nothing positively wrong which is reported about it, but it seems to use custom format and password-to-key processing, which means that it was not well analyzed. I see no mention of an integrity protection. Therefore I would recommend caution until further analysis.

Assuming that AESCrypt does everything right (including integrity checks), then yes, sending by email files which are protected by a password is fine... provided that you choose strong enough passwords, and that you have a way to convey the password to the intended recipient with all the needed confidentiality. It would not buy you much to use both the innate encryption features of RAR and an additional encryption layer, especially if both use the same password.

Systems which support asymmetric encryption like GnuPG will still make your life easier. You still have to make sure that you have the right public key (the one owned by the recipient), but at least it is a public key so you can transmit it securely with less constraints (you can dictate the hash by phone, but you do not have to fear people who merely spy on the phone line, contrary to speaking a password over the phone).

Community
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Thomas Pornin
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    “I see no mention of an integrity protection” The [file format](http://www.aescrypt.com/aes_file_format.html) includes an HMAC. I haven't checked how that field is used, but it's a hint that there is at least an authenticity check. – Gilles 'SO- stop being evil' Oct 05 '12 at 20:05
  • yes, I had already read that discussion, and it's been usefull, thanks @Gilles thanks – webose Oct 05 '12 at 22:21
  • +1 for PGP suggestion, should be a no-brainer even if it's simply for manual exchange of symmetric key and AEScrypt is subsequently used. – deed02392 Nov 26 '13 at 17:13
  • So does anyone know another open-source software that IS well analyzed and meetings all of the conditions above? (for example integrity protection)? Thank you. Also AES Crypt doesn't allow for 256-bit – LearnByReading Feb 09 '16 at 19:08
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AES is a symmetric encrypting algorithm while GPG is meant to provide asymmetric encryption. AES does not provide authentication or integrity. While with GPG you can have both.

With AES you will share a key with someone, whilst with GPG you will be able to share public keys with each other. Meaning a person can verify (providing your private keys do not get stolen) that the file received from your email address is actually also sent by you.

If you encrypt a file with AES to then again rar it with AES you are not really providing too much extra security providing you have a strong key.

Lucas Kauffman
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  • as I reach the 15 reputation point I'll point up this aswer, thanks – webose Oct 05 '12 at 22:27
  • @lucas I would somewhat disagree - Aescrypt does not create a .rar/zip files. I think the question is implying if RAR is used it could add some benefits - meaning that you use another software to encrypt (to achieve .rar) so that there would be two implenetations of the same algorithm - in case one of the screws up – LearnByReading Feb 09 '16 at 19:12
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In order to stop speculations, decrypting altered encrypted file using AESCrypt results in 'Message has been altered and should not be trusted' dialog box coming from reliable HMAC computation and is forbidding decryption. The software is also using random salt, contrary to VSEncryptor, for example.

user71148
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