bash script to encrypt data using a users ssh public key
If you received a message from someone that was encrypted with this script, you can decrypt it with your ssh private key using the following command without installing anything:
bash <(curl -s https://raw.githubusercontent.com/5im-0n/sshenc.sh/master/sshenc.sh) -s ~/.ssh/id_rsa < file-containing-the-encrypted-text.txt
sshenc.sh uses openssl under the hood, so you need to have that installed in your path to make it work.
Install
curl -O https://raw.githubusercontent.com/5im-0n/sshenc.sh/master/sshenc.sh
chmod +x sshenc.sh
Examples
encrypt a file using your own ssh public key
sshenc.sh -p ~/.ssh/id_rsa.pub < plain-text-file.txt > encrypted.txt
encrypt a file using multiple recipients (broadcast encryption)
sshenc.sh -p ~/.ssh/id_rsa.pub -p id_rsa-alice.pub -p id_rsa-bob.pub < plain-text-file.txt > encrypted.txt
encrypt a file using the public key of a github user
sshenc.sh -g S2- < plain-text-file.txt
this line fetches the public keys for the github user S2- and encrypts the file plain-text-file.txt using its key(s).
decrypt a file
sshenc.sh -s ~/.ssh/id_rsa < encrypted.txt
Notes
OpenSSL 1.1.1 introduced a not backwards compatible change: the default digest to create a key from the passphrase changed from md5 to sha-256.
Also, a new -iter parameter to explicitly specify a given number of iterations on the password in deriving the encryption key was added.
Before OpenSSL 1.1.1 this option was not available.
Since the new parameters are more secure, sshenc.sh changed to adopt them, so since 2019-11-26, files encrypted with a previous version of sshenc.sh will not decrypt.
To do so, use the prevous sshenc.sh script, located at https://raw.githubusercontent.com/5im-0n/sshenc.sh/master/sshenc-pre1.1.1.sh.