encrypt messages based on github ssh public keys


encrypt messages based on ssh public keys

It can be frustrating and annoying to communicate with somebody using public key cryptography since setting up PGP/GPG is a hassle, particularly managing keyrings and webs of trust.

Luckily, you can fetch the public ssh keys of anybody on github by going to:$USERNAME.keys

If you just want to send somebody an encrypted message out of the blue and they already have a github account with RSA keys uploaded to it, you can just do:

cipherhub $USERNAME < secret_message.txt

and it will fetch their public keys from github, storing the key locally for next time.

There is an openssl rsautl command to do this but the usage is not particularly friendly and doesn't keep a keyring around.


With npm do:

npm install -g cipherhub

to get the cipherhub command.


cipherhub USERNAME {OPTIONS} < message.txt
  Create an encrypted message for USERNAME on stdin.
  If there isn't yet a local key stored for USERNAME, request a key from$USERNAME.keys
  If there are multiple RSA keys, the operation fails and you will need to
  add the key you want manually with `cipherhub --add`.
  If there are no RSA keys, the command fails with a nonzero exit code.
  OPTIONS are:
    --no-github     don't request key data from github, just fail
    --no-save       don't automatically save keys fetched from github
    --quiet, -q     suppress extra output
    --encoding, -e  output encoding to use. default: base64
cipherhub --add USERNAME <
cipherhub -a USERNAME <
  Set the public key for USERNAME from stdin.
cipherhub --remove USERNAME
cipherhub -r USERNAME
  Remove a USERNAME from the local key list.
cipherhub --list
cipherhub -l
  List all the keys in the local key list.
cipherhub --decrypt PRIVKEY {OPTIONS}
cipherhub -d PRIVKEY {OPTIONS}
  Decrypt a message on stdin with an rsa key file PRIVKEY.
  If PRIVKEY isn't specified, only `-d` by itself, cipherhub uses ~/.ssh/id_rsa
  OPTIONS are:
    --encoding, -e  input encoding. default: base64

crazy ideas

You can create private github issues by just encrypting your message with the maintainer's public key and posting the issue with the ciphertext.

caveat npmtor

github's servers can be compromised by a court order, intruder, or employee. You should use a secondary means of verification to check all the keys fetched from github where secrecy from courts, intruders, and github employees is of paramount importance.