Show HN: Ezcrypt – A file encryption tool (simple, strong, public domain)

by ezcrypt • 2 years ago

37 50 2 years ago

forty2• 2 years ago

This seem to use home made cryptography, which is never a good idea. In particular it's not clear why this design with layered algorithms is needed, nor why it uses a non standard KDF.

Prefer using libsodium for the crypto, which has made sensible choices for you.

forty2• 2 years ago

Also you are missing a MAC, which is also a bad idea

deknos• 2 years ago

what does this provide which cannot be done with openssl, which is available for most systems?

cynicalsecurity• 2 years ago

OpenSSL should not be used for encryption of files. PGP/GnuPG should.

max_• 2 years ago

Why not?

tptacek10• 2 years ago

No, PGP isn't much better.

stackghost• 2 years ago

GnuPG and PGP are a shit show. Just make an encrypted drive volume instead.

SahAssar• 2 years ago

How would you compare this to existing tools in the space like https://github.com/FiloSottile/age?

Seems like age has multiple implementations (rust, go), has a permissive license, a public specification (https://github.com/C2SP/C2SP/blob/main/age.md) and the spec/core implementation is developed by someone with a history with cryptography (I don't know if you do, but there is no indication or name attached to the repo).

While many things can be built as a hobby or learning project I feel like cryptography is one of those spaces where you should be clear if it is that and if it is not you need to expressively argue its bona fides up front.

ezcrypt13• 2 years ago

age is definitely more mature, and as you say, it should probably say somewhere that ezcrypt is still a hobby project (albeit a serious one).

Some motives (some of which may sound strange, but mattered to me):

  * Completely public domain.
  * Without any third party dependencies (not even openssl or similar).
  * Don't rely on a single cipher (low trust).
  * Extremely portable (should easily build for and run on anything from an M4 Mac to a Raspberry Pi to an old OpenWRT MIPS router with 32 MB RAM for instance).
  * Should be easy to use (e.g. no key management, unless you want to), and composable in standard Unix ways (pipes etc).
  * Security focused, obviously. E.g. software architecture-wise, minimize dependencies, properly manage files, processes and secrets, etc.
  * Personally: To learn and to build something that I trust.

In a way: When the dust settles after the nuclear apocalypse, if you manage to dig out a C compiler, this is your tool. ;-)

tptacek10• 2 years ago

"Don't rely on a single cipher" is an anti-goal, and a reason your hobby project won't be taken seriously. You'd be better off striking it from the list.

"Zero dependencies" is also not especially reassuring, as it implies you're using your own cipher implementations (or reference implementations).

some_furry2• 2 years ago

Without any third party dependencies (not even openssl or similar).

In your pursuit of "no dependencies", you made a classic blunder: making AES vulnerable to cache-timing attacks.

https://codeberg.org/ezcrypt/ezcrypt/src/commit/3268d71e80d3...

I'm not going to review the rest of your code. This is sufficient for me to recommend everyone run the other way screaming.

voodooEntity• 2 years ago

I recently gave building a file encryption tool a shot myself ( https://github.com/voodooEntity/go-tachicrypt ) tho i didnt implement my own crypto to be fair.

I think its always good to dive into topics if you are actually interested and lets face it, the beginning of most of the big things nowadays started somewhere in a basement or a garage.

tptacek10• 2 years ago

The code isn't especially easy to follow, but is this a cascade of Serpent, Twofish, ChaCha20, and AES, all in CBC except for ChaCha, without an authenticator? With its own stream construction, that doesn't stop truncation?

ezcrypt13• 2 years ago

That's pretty much spot on. Authentication is planned (and that should handle truncation too if I'm not mistaking): https://codeberg.org/ezcrypt/ezcrypt/issues/3

tptacek10• 2 years ago

Public key signatures and ciphertext authentication are not the same thing.

dist-epoch• 2 years ago

PSA: it should be obvious that it's a really dumb idea to use random new encryption tools from GitHub (sorry, author)

spease• 2 years ago

it should be obvious

It should be, but a lot of developers don’t have formal security training, nor especially management which may end up selecting the contractors/developers and deciding on the technical approach.

If it’s explicitly not production ready, it should probably say so up front, not advertise itself as “strong encryption”. However painful that may be.

ezcrypt13• 2 years ago

All good points. I intend to make it clearer: https://codeberg.org/ezcrypt/ezcrypt/issues/4

sevg• 2 years ago

Don't use this.

It's missing a basic building block: authentication.

Unfortunately, the author hasn't spent long enough researching cryptography. (Even the briefest of research would have made this mistake obvious.)

ezcrypt13• 2 years ago

Very good point!

I have been planning to look into authentication. I didn't need it for my use cases, yet, but as you say that should be an integral part of any serious tool. I added a ticket: https://codeberg.org/ezcrypt/ezcrypt/issues/3

In the meantime, signing and verification can be done separately, e.g. with ssh-keygen, although that is a bit inconvenient (which kind of defeats one of the key points of the tool).

tptacek10• 2 years ago

You can't safely encrypt without authentication, so you do indeed need it.

everfree2• 2 years ago

What’s the advantage over symmetric PGP encryption?

ezcrypt13• 2 years ago

Can you use PGP in the same way (I haven't tried)? Basically, symmetric file encryption based on a secret password and optionally a secret pepper file (effectively a secret key).

everfree2• 2 years ago

Symmetric file encryption yes, key file I’m not aware of.

andrewmcwatters• 2 years ago

Encryption is done in four layers.

What?

tptacek10• 2 years ago

It's a cipher cascade. (Don't build cipher cascades.)

ezcrypt13• 2 years ago

The idea isn't really to make the encryption stronger or to widen the key. It's a classical case of trust - if one cipher is compromised, there are others to cover for you. Also, I wanted to learn the different ciphers, and speed wasn't a top priority.

underlogic• 2 years ago

Why not exactly?

CarpaDorada• 2 years ago

Don't use cryptographic software from people refusing to identify themselves.

ezcrypt13• 2 years ago

This should be the top rated comment ;-) Sorry. I can't remedy the situation for you, though.

gbraad2• 2 years ago

Have used axcrypt before; easy and portable

ezcrypt13• 2 years ago

If it's the AxCrypt I think it is, it doesn't even run on Linux, never mind Raspberry PI or Milk-V for instance. And it's not free either. So it doesn't meet many of my requirements, unfortunately.

svantex2• 2 years ago

I'm the original author of AxCrypt. There's a new compatible iteration of it based on the original cryptography code called Xecrets, with several components. Xecrets Cli is the main fully featured command line engine, free open source GPL on https://github.com/xecrets/xecrets-cli . Xecrets Ez is a simple GUI frontend, single executable, portable. Runs on Linux, macOS and Windows. There are several more components available as nuget packages.

chasil• 2 years ago

What's wrong with "openssl enc"?

sirjaz• 2 years ago

I'm just glad you support Windows. We need more of this!

Show HN: Ezcrypt – A file encryption tool (simple, strong, public domain)

Related Stories