git-caesar

This command encrypts and decrypts files using the public key registered on GitHub and your own private key.

Installation

How to build with GO command

Requires go 1.20 or higher

See below for how to install/upgrade.

go install github.com/yoshi389111/git-caesar@latest

See below for how to uninstall.

go clean -i github.com/yoshi389111/git-caesar

How to install using Homebrew

See below for how to install/upgrade.

brew install yoshi389111/apps/git-caesar

See below for how to uninstall.

brew uninstall yoshi389111/apps/git-caesar

Download from GitHub

Download the file that matches your operating environment from "Releases."

Usage

Usage:

  git-caesar [options]

Application Options:

  -h, --help                    print help and exit.
  -v, --version                 print version and exit.
  -u, --public=<target>         github account, url or file.
  -k, --private=<id_file>       ssh private key file.
  -i, --input=<input_file>      the path of the file to read. default: stdin
  -o, --output=<output_file>    the path of the file to write. default: stdout
  -d, --decrypt                 decryption mode.

• -u specifies the location of the peer's public key. Get from https://github.com/USER_NAME.keys if the one specified looks like a GitHub username. If it starts with http: or https:, it will be fetched from the web. Otherwise, it will be determined as a file path. If you specify a file that looks like GitHub username, specify it with a path (e.g. -u ./octacat). Required for encryption. For decryption, perform signature verification if specified.
• -k Specify your private key. If not specified, it searches ~/.ssh/id_ecdsa, ~/.ssh/id_ed25519, ~/.ssh/id_rsa in order and uses the first one found.
• -i Input file. Plaintext file to be encrypted when encrypting. When decrypting, please specify the ciphertext file to be decrypted. If no options are specified, it reads from standard input.
• -o output file. Outputs to standard output if no option is specified.
• Specify -d for decrypt mode. Encrypted mode if not specified.

Supported algorithms

List of supported public key prefixes:

• ssh-rsa -- Key length is 1024 bits or more
• ecdsa-sha2-nistp256
• ecdsa-sha2-nistp384
• ecdsa-sha2-nistp521
• ssh-ed25519

Unsupported public key prefix list:

• ssh-dss -- DSA
• ssh-rsa -- Key length is less than 1024 bits
• sk-ecdsa-sha2-nistp256@openssh.com
• sk-ssh-ed25519@openssh.com

Example of use

Encrypt your file secret.txt for GitHub user octacat and save it as sceret.zip.

git-caesar -u octacat -i secret.txt -o secret.zip

In the same situation, the private key uses ~/.ssh/id_secret.

git-caesar -u octacat -i secret.txt -o secret.zip -k ~/.ssh/id_secret

Decrypt GitLab user tanuki's file secret.zip and save it as sceret.txt.

git-caesar -d -u https://gitlab.com/tanuki.keys -i secret.zip -o secret.txt

Same situation, no signature verification.

git-caesar -d -i secret.zip -o secret.txt

Related Tech Blog Articles

• dev.to Passwordless encryption with public key for GitHub English
• Qiita GitHub 用の公開鍵でパスワードレスの暗号化/復号をしてみる Japanese

Copyright and License

(C) 2023 SATO, Yoshiyuki

This software is released under the MIT License.