Decryption tools?

Discussion related to AES Crypt, the file encryption software for Windows, Linux, Mac, and Java.
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greenrazi
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Joined: Tue Jul 21, 2020 1:03 am

Decryption tools?

Post by greenrazi »

Hello,

If I encrypt a file using AESCrypt, will I be able to decrypt the file using a standard file decryption tool (provided I enter the same password)?

This is in case I encrypt my files and one day do not have access to the AESCrypt tool.

If such a tool already exists, or if the functionality already exists (for example, as a part of Windows), please educate me as I would like to know before encrypting my files.

Thanks!
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paulej
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Re: Decryption tools?

Post by paulej »

AES Crypt requires a version of AES Crypt to decrypt. However, AES Crypt is open source and documented. Keep a copy of both the binary and source code. That's exactly why I made it open source. I had the exact same concern as you.
jairunet
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Joined: Sun Oct 24, 2021 10:40 am

Re: Decryption tools?

Post by jairunet »

Hello @paulej Thanks so much for simplifying the usage of such a great security protocol, just curious, as asked above, there is no way to open a file .aes with just the opensource Linux security GNU tools?

Per your advise, I downloaded and stored the code of aescrypt for Linux and Windows just to ensure I can open the files five to ten years from today.

Another question is AES is a more secure algorithm than RSA in your opinion?

I will be doing my own due diligence to understand more about the AES algorithm i am not very literate about Math or Cryptography, however, I would love to follow AES down the rabbit hole.

Thanks again in advance!
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paulej
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Re: Decryption tools?

Post by paulej »

GnuPG and AES Crypt are not compatible. Only AES Crypt will open AES Crypt files. That's also true of encrypted file created with OpenSSL. Only OpenSSL can open those.

RSA is a public/private key algorithm. It is not generally used to encrypt data. Rather, it is usually just used to encrypt a key that is used to encrypt the data. Generally, the underlying encryption is AES, TwoFish, BlowFish, ChaCha20, etc.

AES Crypt uses a symmetric key (not public/private key). It does use a key encrypting key algorithm, though, to secure that actual key used to encrypt the bulk of the data. The current version uses a hashing function, whereas the next version I will create will more likely use AES Key Wrap. I already have an implementation of that (https://github.com/paulej/AESKeyWrap), but I will be changing it to not use OpenSSL at all. I did that one for a different project and it will just stay as it is.

Many products implement AES internally for protecting data, so there's nothing unique about AES Crypt in its use of AES. There were two main reasons I wrote AES Crypt: 1) to make it extremely simple for the average user to be able to encrypt data (as most are really just a confusing mess designed for any by programmers), and 2) to ensure the source code is available for everything so that it might outlive me. Like you, I did not want to use a tool that would not be around one day. In fact, another thing I have done (that is largely unknown or unappreciated) is to ensure each new version can read and decrypt every older version. I intend to always do that going forward. That creates a lot of work for me in testing, but it's extremely important to me (and likely anyone else using AES Crypt) to ensure no future version just stops reading old files.
jairunet
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Joined: Sun Oct 24, 2021 10:40 am

Re: Decryption tools?

Post by jairunet »

Hello Paul,

Thank you again for the prompt response, very informative and helpful, I will continue learning about the usage of AES, AEScrypt and understanding more about encryption with symmetric and asymmetric techniques.

Keep up the great work, the tools is so simple and great, no mention the super cool details of you improving the tool while maintaining backward compatibility.

Chat soon!
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