Brute force an SSH key for custom branding!

How it works

To get a desired word like book or worm in a key, we can use bruter to automatically generate a large amount of keys and check the content of the public key until we find one that we like.

To indiscriminately find the words book or worm in a public key, we can use the following command:

bruter -C myemail@gmail.com -s "book,worm"
#                           ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ ↖ filter to containing 'book' or 'worm'

# This executed on my computer with an `AMD 5800X3D` in 640ms:
# ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIABOoKthRZZ0DbDwsxzvStDIpqXJowdo8z1/XVcdRO/+ myemail@gmail.com
#                                       ‾‾‾‾ ↖ it found it!

This might be too obscure to be cool so it's possible to only filter the results down to the end:

bruter -C myemail@gmail.com --suffix-only -s "book,worm"
#                           ‾‾‾‾‾‾‾‾‾‾‾‾‾‾ ↖ filter down to only suffixes

# This executed on my computer with an `AMD 5800X3D` in 17.33s:
# ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBnTme8nnHxP21BgXv9c/i9GesmkC0xrtAV/LF7CBOOK myemail@gmail.com
#                                                                             ‾‾‾‾ ↖ the result is at the end

If you really want to get super specific, there is always the --case-sensitive flag too.

Tip

Use the -j flag to increase the amount of threads the program uses

Tip

The --help shows a lot of useful information on how to filter to a specific desired result

Just remember it's all luck based! The more specific the search, the longer it'll take. Happy hunting!

Compiling / Running

If you want to download and use it right away, you can use the badge above to go to the downloads page and simply select the platform you're on and download it.

To compile it, you'll need the 0.13.0 release of Zig and binaries can be found here.

It's recommended that if you want to get good keys/sec to compile in fast mode:

zig build -Dtarget=native -Doptimize=ReleaseFast
# the result will be: zig-out/bin/bruter

Contributing

Open an issue and if everything seems cool, you can make a PR!

Retrospective

History:

• The improvised/slapped together Rust version of this project on 16 threads: ~100 keys/sec
• This version on 1 thread without optimizations: ~1,400 keys/sec
• This version on 1 thread WITH optimizations: ~18,000 keys/sec

It was probably bad and slow to have the old version written in Rust just spawn processes when you can get comparable (?) cryptographic quality randomness on a thread local level and just do the key generation in the process.