yage: yaml age

A simple tool to manage encrypted secrets in YAML files with age encryption.

yage is using age encryption to encrypt the values in a YAML file while keeping the keys unchanged.

A simple yaml file like this one:

backend:
  url: https://example.com
  username: gaspard
  password: api_s3cr3t_k3y

is encrypted by yage to:

backend:
  url: yage[YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSA1KzZiNVVvTThaQ0dSbVZBMElRUEpZRlVxb1VaamU3SGtWRWxseFBHMkVNClBsUGJMWFJ0MnA0czA0MEE0VnRjY3Q3VnE4NElpUHQ2aTNKUlVMOUJnbEUKLT4gZGVVYFRQcVwtZ3JlYXNlIHR+OSVVZyMhCituclJ0ZTZJU1grSmpxaTZvb2hMYlBvMnpIbGFja0ltRm9BdE9sTVJ5RG14RkhNaXNsc0xUbUViT1lyRVh6dWYKdHRsVU10SHJ1YytaY2hhdWdjQ0lJVnFkczJFcHBMMXl3QTNEQUc1SW9YM0hscGZVbEdPdWZWTQotLS0gcTVIZzZrdnVJNGNoNm51UEE1alJHVmJsQnRMdStuVXU0Q1pJSzFzVlU1QQqH64hS0UV4JI6CtYHpSCEslxLqi3764zaxF/VJy67gQOBrj2TV1z6NwJaBmlUPBQB2zROq|r:age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6]
  username: yage[YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBVU2tuOWFpV2NDT05DSC9FbHNadzVVTTJmSFQwekRjRjZiOERDVTZ0aGdnCnhKTGpQcGY1SUw0bFd2cFhudC9yY1I0VTJxWklBYUkvYlhzNHhUeCtIVmsKLT4gTGJ+LWdyZWFzZSAhClJlTU5TZ3NldGRaRzRGQThOZmMrdkFnS0NzUnBpMmFpRTM4d0hGQXEKLS0tIGQvSXIxcXpDYk9yTU9ERDlEMHV1d0VmTGovWU9SVkJ5TkswYS9rMmdGbHMK3GehcWJL1GUKFGLJXQFGUQLhs56mgHRYpBIsFgYpyW818dG27bz1jQ==|r:age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6]
  password: yage[YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSAyRVUyTHpmQnZuTlc5MGJhODFuSE5WMmdzalNid0ExamliNDREbWlJUXdvClFhS3JGSGV2cjlnL0dWUnNwSDNvWGVHUDVDendkNzFWWXJCcTNDTVJNLzgKLT4geW0tZ3JlYXNlIF8zJ3MpXksKeXRwMW9aeitydwotLS0gWVNjbnZsUmNRWTdtM0pjVjNKQjBDZ1k2cVNhcWkwMnAxREwwMXptREhLZwrpCkrMFiq/XWfAyFRrLuLkkEPhnZ9Kt68pg5ENgDTV9+3iRcy6XKYdkqnEBRidMg==|r:age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6]

Having the keys unencrypted allows to easily manage the file in a version control system, like git, and to use this file in a CI/CD pipeline or in a gitops workflows.

If you think this looks a lot like SOPS, you're right! This is basically what SOPS is doing, but we some key differences:

• yage doesn't include any metadata in the encrypted file, in particular no MAC.
• yage is focused on age encryption, and include everything required in a single binary.

The lack of MAC, while it could be seen as a missed opportunity to add some security, actually allows some interesting use cases:

• the encrypted file can modified by someone that only has the public key, while still preserving the encrypted values.
• the encrypted file can modified by multiple persons and merged in a version control system without having to decrypt it first.
• the encrypted file only contains the original keys and the encrypted values, so it can be used to verify that it is usable for a specific task without having to decrypt it or remove the metadata.

Installation

From binaries

Go to the releases page, download the binary for your platform, extract it and put the yage binary in a directory in your PATH.

For example on linux with an intel/amd64 processor, you can run the following commands to install yage in ~/.local/bin:

curl -ssL https://github.com/glehmann/yage/releases/download/0.5.0/yage-0.5.0-linux-amd64.tar.gz | tar xzf - -C ~/.local/bin --strip-components=1

Docker

yage is also available as a docker image.

Here is how you can use it to encrypt a file in place:

docker run --rm -t -v $(pwd):/src ghcr.io/glehmann/yage:0.5.0 encrypt -iR prod.pub secrets.yaml

From source

Just run

$ cargo install --path .

in this repository

Command line reference

yage comes with a full description of its commands and options. Just run yage --help to get it.

$ yage --help
A simple tool to manage encrypted secrets in YAML files with age encryption

Usage: yage [OPTIONS] [COMMAND]

Commands:
  check       Check the encryption status of a YAML file
  decrypt     Decrypt the values in a YAML file
  edit        Edit an encrypted YAML file
  encrypt     Encrypt the values in a YAML file
  env         Execute a command with the environment from the encrypted YAML file
  keygen      Generate a new age key
  pubkey      Convert private age keys to their public key
  recipients  List the recipients of the encrypted data
  re-encrypt  Re-encrypt the values in a YAML file
  help        Print this message or the help of the given subcommand(s)

Options:
      --completion <SHELL>  Generate the completion code for this shell [possible values:
                            bash, elvish, fish, powershell, zsh]
  -v, --verbose...          Increase logging verbosity
  -q, --quiet...            Decrease logging verbosity
  -h, --help                Print help
  -V, --version             Print version

See also the markdown version of the command line reference.

You may also find convenient to install the completion for your shell. For example for fish:

$ yage --completion fish > ~/.config/fish/completions/yage.fish

Usage

First generate a new age key pair:

$ yage keygen -o prod.key -p prod.pub
Public key: age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6

The public key can be shared with anyone. It allows everybody that has that key to encrypt a secret that can be decrypted only by someone who has access to the private key. The private key must be kept secret.

Both keys are just text:

$ cat prod.key
AGE-SECRET-KEY-1EZEU9RUTW3K5GV98ER6RHMS73QJNQ37ARWG6MWHXM4JP8FVD3A9QK2DD70

The public key could be committed to a git repository:

$ git add prod.pub
$ git commit -m "Add prod public key"

Make sure that the private key won't be committed by mistake in the repository, for example by adding it to the .gitignore file, and by using a tool like gitleaks.

$ echo "*.key" > .gitignore

The private key should be kept in a secure place, for example in a password manager. It may also be added to a CI/CD pipeline as a secret.

Once you have a private and a public key, you can encrypt a YAML file. The --recipient-file or -R option is used to specify a file containing the public keys to use for encryption. The recipients can also be specified directly on the command line with the --recipient or -r option.

$ yage encrypt --recipient-file prod.pub secrets.yaml --output secrets.enc.yaml

If you prefer you can encrypt the file in place wit the --in-place or -i option:

$ yage encrypt -iR prod.pub secrets.yaml

You need the private key to have access to the decrypted values, so if you don't have it, the encrypted file is showing you what is encrypted, for example backend.password, but not the values.

backend:
  password: yage[YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBRVW9wTXo0dG9lWTRyd1gxdm8yTGNOb1VuQWZSajBETzF4YThMbVVGM21FCjBTQXZxVDIvTWxGd1N6YXlUTHpoVlMzbTVURDZHcXBYaVc5NitYaE1LSW8KLT4gayMtZ3JlYXNlIFwganwhJUcyS1QgTT5sWTMzblYKCi0tLSBLUnREbytjalY3Rm45aEdVVnIzWG8yWC9RUVdlK1A4Mm9BSFdtamg5N2RNCm38HthiQvHqtUIu6+wKOyOH0WShltaeTGk2Qilym+9WFFb0n8g5Eb/6|r:age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6]

But with just the public key, you can still modify the file, for example to add a new secret:

mail:
  apiKey: my_secret_key_to_send_emails
backend:
  password: yage[YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBRVW9wTXo0dG9lWTRyd1gxdm8yTGNOb1VuQWZSajBETzF4YThMbVVGM21FCjBTQXZxVDIvTWxGd1N6YXlUTHpoVlMzbTVURDZHcXBYaVc5NitYaE1LSW8KLT4gayMtZ3JlYXNlIFwganwhJUcyS1QgTT5sWTMzblYKCi0tLSBLUnREbytjalY3Rm45aEdVVnIzWG8yWC9RUVdlK1A4Mm9BSFdtamg5N2RNCm38HthiQvHqtUIu6+wKOyOH0WShltaeTGk2Qilym+9WFFb0n8g5Eb/6|r:age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6]

You can encrypt the new secrets by just using the same command as before:

$ yage encrypt -iR prod.pub secrets.yaml

Or you can omit the recipients, and yage will use the recipients from the encrypted file:

$ yage encrypt -i secrets.yaml

secrets.yaml now contains the encrypted values:

mail:
  apiKey: yage[YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBPTmRHcGhPUnJQa2ZjbTVEUEtyT3g1bFd5REdnckF6Z0ZLQzlTekV5THdJCkoybXY3SEI2N3FTcXlHenByRHJOVGFtR2VRUWFBWGhEOGphbkd2ekV3bVkKLT4geUt2b0I2Ly1ncmVhc2UKODVocmxxODlZME1Sa1UvV2RnQkNPcjhvTWpZZFlKYzNkQmsKLS0tIHhsNEpvYzNwT1FMd1c2bmxLQmxOeGZxWnlXbDJUUmVsTklxZVIweUxSQXcK51Wf0RiFIAXYfsbmyMsyQRON5rhQxver8PUU8PDAMIm0XeBSKOzL3ngCmOKGeacahMOY5tWC6DgP20MrtQ==|r:age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6]
backend:
  password: yage[YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBRVW9wTXo0dG9lWTRyd1gxdm8yTGNOb1VuQWZSajBETzF4YThMbVVGM21FCjBTQXZxVDIvTWxGd1N6YXlUTHpoVlMzbTVURDZHcXBYaVc5NitYaE1LSW8KLT4gayMtZ3JlYXNlIFwganwhJUcyS1QgTT5sWTMzblYKCi0tLSBLUnREbytjalY3Rm45aEdVVnIzWG8yWC9RUVdlK1A4Mm9BSFdtamg5N2RNCm38HthiQvHqtUIu6+wKOyOH0WShltaeTGk2Qilym+9WFFb0n8g5Eb/6|r:age15eesfkh778yljxzgwdq5vaqmmchg5py480vplsymzzqf0dwe5gnqrexdq6]

Note that backend.password has not been re-encrypted, so you can easily track the changes in your version control system.

To decrypt the file, you need the private key:

$ yage decrypt --key-file prod.key secrets.enc.yaml --output secrets.yaml

Or just do it in place:

$ yage decrypt -iK prod.key secrets.yaml

If your decrypting in a CI/CD pipeline, you may find convenient to put the private key in the YAGE_KEY environment variable. This way you can just use yage decrypt -i secrets.yaml.

You may also find convenient to pass the private key on the standard input, for example to avoid storing the private key on disk:

$ vault-get-key | yage decrypt --key-file - secrets.yaml

If you have the private key, you can edit the file in place with your favorite text editor configured in the EDITOR environment variable:

$ export EDITOR=micro
$ yage edit -K prod.key secrets.yaml

The file is edited in clear in the editor and re-encrypted when you save and quit. Here again only the modified values are re-encrypted. The others are left unchanged to allow easy tracking of changes.

Finally, with the private key, you can use the secrets in the encrypted file to run a command with the environment variables set to the decrypted values in a single command:

$ yage run -K prod.key secrets.yaml env terraform apply

Pre-commit hook

yage can be used in a pre-commit hook to make sure that the secrets are always encrypted before committing them to the repository. Here is an example of a .pre-commit-config.yaml file that uses yage to detect the non-encrypted secrets in a YAML file before committing them:

repos:
  - repo: https://github.com/glehmann/yage
    rev: 0.5.0
    hooks:
      - id: yage-detect
        files: "secrets-.+\\.yaml"

The files option is a regular expression that matches the files that should be checked by yage.

If your public key is in the repository, you can also add a hook to encrypt the secrets before committing them:

repos:
  - repo: https://github.com/glehmann/yage
    rev: 0.5.0
    hooks:
      - id: yage-encrypt
        files: "secrets-prod-.+\\.yaml"
        args: ["--in-place", "--recipient-file=prod.pub"]

yage-detect and yage-encrypt hooks require the yage binary to be installed in the environment where the hook is running.

The yage-detect-rust and yage-encrypt-rust hooks are other available variants that build yage from source.

If you're already using docker in your project, the easiest alternatives are the yage-detect-docker and yage-encrypt-docker hooks. They only require docker to be installed in the environment where the hook is running. The yage image is downloaded automatically when the hook is run for the first time.

Why?

Mostly to unlock the ability to add values to an encrypted file without having to decrypt it, thing that is not possible with SOPS. Something I've not been the only one frustrated with, see here, here, here, here, …

And because writing command line tools in rust is fun!

Still to be done

• Support comments. Sadly no YAML library that I know of supports comments, so this will be a bit tricky.
• Support age plugins. age has a plugin system that could be used to add support for other encryption methods.
• Support multi-document YAML files. This could help to make the CLI more consistent between in place and standard output operations.

License

yage is distributed under the terms of the MIT license.

See LICENSE for details.