A small project to play around with libsodium

The idea

Learn something about libsodium, which is now also part of Vim (see patch 8.2.3022).

So here is a small utility, that let's you encrypt and decrypt messages, that can also be read by Vim.

You can use the old and new Vim cryptmethod:

cryptmethod: 'xchacha20' - cryptmethod 'xchacha20', requires vim 8.2.3022
cryptmethod: 'xchacha20v2' - new cryptmethod, requires Vim v9.0.1481

Install

~$ apt install libsodium-dev # libsodium is required to build
~$ git clone https://github.com/chrisbra/vimcrypt
~$ cd vimcrypt; make

Different Xchacha20 Versions

The difference between the new xchacha20v2 and the old xchacha20 is basically, that the new method also stores the parameters required for correct key-derivation:

- opslimit: the maximum amount of computations to perform. By default, this is OPSLIMIT_INTERACTIVE.
- memlimit: the amount of memory you want to reserve for password hashing. By default, this is MEMLIMIT_INTERACTIVE
- alg:      the algorithm used for the key derivation. By default, this is '2' (ARGON2ID13)

Usage

~$ vimcrypt encrypt file  # encrypt
~$ vimcrypt decrypt file.enc # decrypt

By default, when encrypting, it will leave your precious input files alone and write the encrypted file to the same name with the suffix .enc added.

That means, you need to decrypt files with the name <input>.enc.

Arguments:

-v        -  be verbose
-b <nr>   -  Use <nr> as block size for encryption
-V 1      -  Use xchacha20 (old) libsodium version
-V 2      -  Use xchacha20v2 libsodium vim version

This matters mostly for files larger than the block size, because if the wrong block size is given, the file won't be decrypted properly. By default, Vim uses a block size of 8192 Bytes, so this script also uses 8K block size if no one is given.

License & Copyright

NO WARRANTY, EXPRESS OR IMPLIED. USE AT-YOUR-OWN-RISK