#file #back #turn #secret #encryption #again #de-gibberish

app gibberish

Turns files into gibberish and back again

1 unstable release

0.1.0 Mar 8, 2019

#1904 in Cryptography

24 downloads per month

MIT license

127 lines

Turn files into gibberish, then de-gibberish them to get back the original file. Also known as encryption, but we don't want to get pretentious here, plus gibberish isn't really secret if you don't set a password.


If you got the Rust tools installed, you can use Cargo:

cargo install gibberish

If you don't, you'll have to wait a bit. Gibberish is in development, there are no precompiled binaries just yet.


Engibberish files with the gibberish command:

$ gibberish file.png
Gibberish written to file.gibberish

(Is 'engibberish' this even a word? Well, now it certainly is...)

Then de-gibberish them with gibberish -d:

$ gibberish -d file.gibberish
Decoded gibberish to file.png

The gibberish file format stores the extension. You can use it for any kind of file, all of them will be encoded to an extension of your choice (defaults to 'gibberish'), and decoded to the original extension.

Advanced Usage

Password Locking

You can set a password on your gibberish:

$ gibberish -p secret.png
Confirm passphrase:
Gibberish written to secret.gibberish

$ gibberish -d -p secret.gibberish
Decoded gibberish to secret.png

This gives you similar-looking gibberish, but it will be encrypted with the password you provided. The encryption standard is NaCl's Secretbox (xsalsa20poly1305), with the password derived using libsodium's default password hasher (scryptsalsa208sha256). In layman's terms, it's strong enough that your password is going to be the weakest point.

File Extension

You can set any extension to your output gibberish:

$ gibberish -e docx hidden.png
Gibberish written to hidden.docx

$ gibberish -d hidden.docx
Decoded gibberish to hidden.png

It's important to note that all gibberish files are encrypted, but if you don't provide one, the extension of the output file is the password. In other words, file.gibberish was encrypted with "gibberish" as the password, and hidden.docx uses "docx" (unless you set a password yourself).

This also means that if you rename hidden.docx to, say, hidden.xlsx, it will fail to de-gibberish, because it will try to use "xlsx" as the password while it was gibberished with "docx".

$ gibberish -e docx hidden.png
Gibberish written to hidden.docx

$ mv hidden.docx hidden.xlsx

$ gibberish -d hidden.xlsx
Error: failed to decode gibberish

In this case, just enter the original extension ("docx" in this case) as the password:

$ gibberish -d -p hidden.xlsx
Decoded gibberish to hidden.png


Gibberish is intended to be a clean and simple way of exchanging files across automated filters. Say, you wanted to send a meme.gif file to someone, but the chat app you use disallows gif files for some weird reason, or processes them and destroys the quality in the process. Perhaps you want to send a photos.rar archive of the photos from your last trip, but the app disallows rar files in fear of someone putting a virus in them. We've all seen these filters, and while they clearly have some use, they often go way too far and are a hassle.

With gibberish, you can easily solve this issue. You can just turn a file into gibberish, and then your recipient can de-gibberish the file. Simple, clean, easy. No need for password-locked rar files or anything crazy and complex.

File format

The gibberish file consists of three concatenated binary fields:

Name Length Description
Salt 32 bytes The salt for password hashing
Nonce 24 bytes The nonce for the secretbox
Content rest of file A secretbox, containing the file

Inside the secretbox, there is a MessagePack object in the following layout:

Map {
  "extension": String,
  "file": Binary

Where the value of the "extension" field is the original file extension, and the value associated to the "file" key is the content of the original file.

Filter Avoidance

While simple in format, this file is very hard to filter.

  • The file itself looks completely random. The content field looks random, and the other two fields are actually random. There is no magic number, no public metadata, nothing to distinguish a gibberish from a random binary. You could say it looks like gibberish.
  • Any file, with any extension can be gibberish, it is not limited to *.gibberish.
  • Even if the key is public (the gibberish has no password set to it and has not been renamed) you have to hash the entire file to detect gibberish.
  • Even if you do the above check, users can easily rename the file, use a different extension, or set a password, rendering your filter useless.

The point of gibberish is that you have to follow and understand the conversation to tell it apart from randomness, and that's something only humans can do. For now, at least.

If you're a user of gibberish, reading this, just set a password and tell your recipient what it is.


While the core algorithm is ready, gibberish still needs significant quality of life improvements before it can be ready for its job, including:

  • A simple, friendly user interface
  • Precompiled binaries because no one's gonna install rustup
  • Shell integration on Windows (and maybe Linux)
  • Mac support? If you develop for those things, PRs are welcome
  • Mobile apps (figure out how the UX should even look, in the first place)
  • A website, maybe (low priority)

As you can see, gibberish is barely anything more than a proof of concept at this stage.


Pull requests, issues, and ideas are welcome, feel free use github like it was reddit. Just a few rules: don't do anything illegal and respect each other.

Gibberish is available under the MIT license.


~243K SLoC