alexcb / secretshare

a command line tool for using public/private key encryption for encrypting data on the command line

Share secrets using rsa public/private encryption.

Installation

Linux-amd64 (e.g. intel)

sudo /bin/sh -c 'wget https://github.com/alexcb/secretshare/releases/latest/download/secretshare-linux-amd64 -O /usr/local/bin/secretshare && chmod +x /usr/local/bin/secretshare'

Linux-arm64 (e.g. raspberry pi v4)

sudo /bin/sh -c 'wget https://github.com/alexcb/secretshare/releases/latest/download/secretshare-linux-arm64 -O /usr/local/bin/secretshare && chmod +x /usr/local/bin/secretshare'

MacOS-amd64 (e.g. intel)

sudo /bin/sh -c 'wget https://github.com/alexcb/secretshare/releases/latest/download/secretshare-darwin-amd64 -O /usr/local/bin/secretshare && chmod +x /usr/local/bin/secretshare'

MacOS-arm64 (e.g. M1/M2)

sudo /bin/sh -c 'wget https://github.com/alexcb/secretshare/releases/latest/download/secretshare-darwin-arm64 -O /usr/local/bin/secretshare && chmod +x /usr/local/bin/secretshare'

Usage

Suppose Bob wants to receive some data from Alice, first Bob must run secretshare locally:

secretshare

This will generate a new public/private key, and will then print out a help message containing Bob's public key:

To decrypt data, run: secretshare < file_to_decrypt
To encrypt data, run: secretshare <encryption_key> < data_to_encrypt

For example if someone wanted to send you data, they would run:
secretshare AAAAB3NzaC1yc2EAAAADAQABAAABAQCagdQYuPXgzyfg2k58CYTntkSo2rI9QtZWYnk45n6oZGW8wGUoqrmCeLCbCo7HG6JJD+jUuWx9ELmC2rRINQnhJdBdwbMlOx8v7oSr60xR8b0pYRL1gm6DseU0u/pClBfGcwV7tsxuRspk/c3/cpYOFcs2vN5mXo29qSpg1w4iE3snoAOQGajN1U4sT3rht5hjx188d9MxuBTnqd0yW7RQMSS8YqdszaAiwUQ2rtwMKDUp5CT+5LZ/QW/EMexRSEfgkjGGmz+NlBAhGDTrBByw2Dl+6pZESAtxmCaZ6vzG+CSqH5oQVXVl/A9YEQiuDVGdxcfF3jYmlYIfISeMtRTj < data_to_send

Bob can then safely copy and paste his public key, and send it to Alice.

Alice will then run:

echo 'Hi Bob, your new password is "querty".' | secretshare AAAAB3NzaC1yc2EAAAADAQABAAABAQCagdQYuPXgzyfg2k58CYTntkSo2rI9QtZWYnk45n6oZGW8wGUoqrmCeLCbCo7HG6JJD+jUuWx9ELmC2rRINQnhJdBdwbMlOx8v7oSr60xR8b0pYRL1gm6DseU0u/pClBfGcwV7tsxuRspk/c3/cpYOFcs2vN5mXo29qSpg1w4iE3snoAOQGajN1U4sT3rht5hjx188d9MxuBTnqd0yW7RQMSS8YqdszaAiwUQ2rtwMKDUp5CT+5LZ/QW/EMexRSEfgkjGGmz+NlBAhGDTrBByw2Dl+6pZESAtxmCaZ6vzG+CSqH5oQVXVl/A9YEQiuDVGdxcfF3jYmlYIfISeMtRTj

Which will output an encrypted message:

gevonaUXKj7Wmct65A8yVJWTp9D/sd6YbOCi4BtrKGeUjdWs/fa0BbP0IQhdP2j4fS6n12zGmgkOXHLJyJnG9OPxZ+EaPcIfVBs5TfvNnC/8Dfu+V5ScRIYXBHVjRsDOBQCYzeOSwFvq1vUyuq20Wr7s3szbgFkDttxPsaXMKyxTcVEqkgSp09dhV7roqBmsRUDbAFpIWLIUb4ZAtCfU6rbWaAes9acSmMT3fvW/no1gsa3/Wobdpj3T7WVrQsj+upr2ANlFyA3Bt7IOKxmJhrrRYOBxAkk6NEnYmrHWR26KGRhz/VRPxAZWsB/qMoVAw5ukjnVple2+x8SMrIE9Gg==

Alice can then safely send this data back to Bob, who can decrypt it by running:

echo "gevonaUXKj7Wmct65A8yVJWTp9D/sd6YbOCi4BtrKGeUjdWs/fa0BbP0IQhdP2j4fS6n12zGmgkOXHLJyJnG9OPxZ+EaPcIfVBs5TfvNnC/8Dfu+V5ScRIYXBHVjRsDOBQCYzeOSwFvq1vUyuq20Wr7s3szbgFkDttxPsaXMKyxTcVEqkgSp09dhV7roqBmsRUDbAFpIWLIUb4ZAtCfU6rbWaAes9acSmMT3fvW/no1gsa3/Wobdpj3T7WVrQsj+upr2ANlFyA3Bt7IOKxmJhrrRYOBxAkk6NEnYmrHWR26KGRhz/VRPxAZWsB/qMoVAw5ukjnVple2+x8SMrIE9Gg==" | secretshare

Which will output the original message:

Hi Bob, your new password is "querty".

Under the hood

Under the hood secretshare will generate a private and public key stored under ~/.secretshare and ~/.secretshare.pub respectively. The public key is what is used by alice to encrypt data that can only be decrypted using the private key. If we cat ~/.secretshare.pub, we can see the same data is sent in the above usage example:

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCagdQYuPXgzyfg2k58CYTntkSo2rI9QtZWYnk45n6oZGW8wGUoqrmCeLCbCo7HG6JJD+jUuWx9ELmC2rRINQnhJdBdwbMlOx8v7oSr60xR8b0pYRL1gm6DseU0u/pClBfGcwV7tsxuRspk/c3/cpYOFcs2vN5mXo29qSpg1w4iE3snoAOQGajN1U4sT3rht5hjx188d9MxuBTnqd0yW7RQMSS8YqdszaAiwUQ2rtwMKDUp5CT+5LZ/QW/EMexRSEfgkjGGmz+NlBAhGDTrBByw2Dl+6pZESAtxmCaZ6vzG+CSqH5oQVXVl/A9YEQiuDVGdxcfF3jYmlYIfISeMtRTj

Building from Source

secretshare makes use of the Earthly build system. To build from source, first download the earthly command, then run:

earthly +secretshare-all

which will produce binary files under ./build/<platform>/amd64/secretshare

Release

To release a new version, run the following command:

RELEASE_TAG=v0.0.2 earthly --build-arg RELEASE_TAG --secret GITHUB_TOKEN --push +release

Preview