@control/sign

This is a very simple utility to sign or encrypt files or random input with an RSA key pair.

Signing with a keypair allows you to broadcast your public key and transmit digital signatures so other people can trust whatever content you sent was not tampered with.

Encrypting is used the other way around, you are supposed to encrypt a file using someone else's public key, so they can decrypt it using their private key. Since RSA cannot encrypt too much data, this package creates a random 32 char password that it uses to perform the encryption. This password is then encrypted via RSA and sent along with the encrypted file. Anyone else who receives the file should need the receipients private RSA key to decrypt the password, and thus the file.

Keys

By default @control/sign uses your default id_rsa key from your .ssh folder. You can of course specify any other key if needed.

Please note that the keys (both private and public) must be in pem format.

Usually your public RSA key would be generated for SSH, and should be in ssh-rsa format.

In order to export your public RSA key into pem format you can use the following command:

ssh-keygen -f my_key.pub -e -m pem > my_key.pub.pem

GitHub sharing keys

GitHub automatically shares your public keys with the world, just head over to github.com/:username.keys, for example my public key is located at github.com/jsmrcaga.keys.

Usage

Installation

npm i -g @control/sign

Common arguments

Argument	Required	Default value	Description
-i, --input	No	-	The input to sign/verify
-k, --key	No	~/.ssh/id_rsa for private keys, ~/.ssh/id_rsa.pub.pem for pubic keys	The public key used to verify, or private key used to sign
-f, --format	No	'base64'	The format used to export the signature

Signing

Signing input:

sign -i <my input>

Signing a file:

sign my_file.ext

exporting :

sign -o my.signature my_file.ext

Verifying

verify -s <signature.file> file-to-verify.ext

Encrypting

encrypt -o file.encrypted -k bobs-public-key.pem file.txt

Decrypting

decrypt file.encrypted

To a file

decrypt -o file.txt file.encrypted

decrypt file.encrypted > file.txt