harpo 1.4.2

A GPG-based secret storing/sharing library

Description

Harpocrates (Ancient Greek: Ἁρποκράτης) was the god of silence, secrets and confidentiality.

Harpo is GPG-based secret storage/sharing library.

It is aims to be a convenient wrapper around GPG and tries to solve the following problems:

• Storing secrets in a repository in a secure manner

• Providing a group-based access to the stored secrets

• Providing an easy way to re-encrypt secrets

It was inspired by blackbox by StackExchange.

Quick Start

Initialize

Initialize harpo in a current directory:

harpo system init

This will create .harpo directory that will contain your secrets and all required metadata.

Create Domain

Domain — is a ‘directory’ for secrets. To be honest, it is a directory that contains GPG-encrypted files, plus some metadata.

Let’s create one and name it secrets:

harpo domain create secrets

Create User

User is a Harpo’s word for ‘recipient’. A User must have a GPG key attached to it so that Harpo will use it then to encrypt secrets.

The process of adding a user consists of two steps: add a key, create a user associated with this key:

1. add a key

This guide assumes that you already have your GPG key in your default keyring. Let’s export your GPG public key and add it to Harpo:

gpg --export --armor your-key-fingerprint | harpo key create -

2. create a user

The following command will create a user named alice associated with your GPG public key:

harpo user create alice your-key-fingerprint

Let’s verify by running harpo user list. The output should look like:

+--------+------------------------------------------+
| name   | key_fingerprint                          |
|--------+------------------------------------------|
| alice  | A8EE4ED8DDFC3EFFD26EC0042477DBC294CF0AF0 |
+--------+------------------------------------------+

Create Group (optional)

While you can skip this step if you have just one or two users, it’s just a lot more convenient to organize your users into groups if you have many of them.

Let’s create a group and add Alice to it:

harpo group create admins
harpo group members add admins alice

You can verify with harpo group list that will return you a flat list:

admins
developers
users

You can also list a groups table with members using harpo group list --members:

+--------+-----------+
| name   | members   |
|--------+-----------|
| admins | ['alice'] |
+--------+-----------+

Grant access to Domain

Now we have to tell Harpo that our user/group should be able to manage secrets in Domain secrets:

harpo domain allow secrets %admins

Note the % character! Just like in sudoers, this character tells the program to treat admins as a group.

OR

If you want to grant access just to a user, not a group:

harpo domain allow secrets alice

You can verify this with harpo domain info secrets:

+---------+----------+-------------+--------+----------------------+-----------+--------------+
| name    | parent   | allow       | deny   | inherit_recipients   | comment   | recipients   |
|---------+----------+-------------+--------+----------------------+-----------+--------------|
| secrets | None     | ['%admins'] | []     | True                 | None      | ['alice']    |
+---------+----------+-------------+--------+----------------------+-----------+--------------+

In column allow you can see users and groups that have access to this domain.

In column recipients you can see a final set of recipients for this domain. These users will be the recipients of a GPG-encrypted secret that Harpo will create.

Create a secret

Finally we can encrypt something.

You have two slightly different ways of creating a secret using Harpo CLI. Let’s go through them:

1. pass secret value as an argument

harpo secret create [OPTIONS] DOMAIN_NAME SECRET_NAME SECRET_VALUE

harpo secret create secrets foo bar

2. interactive editor (beta)

You also have an option to launch your favorite editor!

harpo secret edit secrets foo

VIM users: There is a known issue with vim when backup files are enabled - Harpo won’t save your edits at all. You can disable backup files with nobackup directive.

Read a secret

This is pretty straightforward:

harpo secret read secrets foo

Documentation

Domain

Domain — is a logical group of secrets. You can think of domain as a directory that contains secrets and other domains.

Properties

Domains have following properties:

• name — the name of a Domain

• children — each Domain can have any number of subdomains, i.e. children. By default all permissions are inherited from the parent to children. This property is not stored in metadata but instead populated in runtime.

• parent — Every Domain has a parent except the root (top level) Domains. Root Domains has no parents.

• allow — list of Groups and Users that have access to this Domain.

• deny — list of Groups and Users that are explicitly denied to become a recipients for secrets in this Domain.

• recipients — a set of Users that are derived from the list of (allow - deny) that have access to this Domain. This property is not stored in metadata but instead populated in runtime.

• inherit_recipients — controls how a given Domain should inherit recipients from its parent. Currently only two modes are available: True and False. Inheritance can be disabled during Domain creation from CLI by adding --no-inherit-recipients flag.

Storage & metadata

Domains are mapped to filesystem as directories and can be found in .harpo/data.

Every Domain also has an associated metadata in .harpo/meta/domain.json.

Key

Key is one of the simplest entities in Harpo. It’s just that: a GPG public key that is stored in the Harpo’s keyring.

Properties

• fingerprint — GPG key fingerprint; the main property of a Key

Storage & metadata

Harpo’s keyring can be found in .harpo/keystore/pubring.gpg.

Keys don’t use any metadata.

User

In Harpo prior 1.0 users were represented by GPG keys only. Harpo 1.0 adds a new separate entity for users.

This being said, Users are still mapped to Keys as 1-to-1, but this probably will change in the future (allowing a single User to have multiple GPG keys, for example).

Currently User is just a named mapping to a Key.

Properties

• name — the name of a User

• key_fingerprint — a GPG key fingerprint of a key that is associated with this User.

Storage & metadata

Users metadata can be found in .harpo/meta/user.json

Group

Group — is a set of Users. Currently groups can’t contain other groups.

Properties

• name — the name of a Group

• members — list of members

Storage & metadata

Groups metadata can be found in .harpo/meta/group.json

Secret

Secret — is a GPG-encrypted data inside Domain.

To encrypt a secret Harpo needs to know the list of recipients. Harpo gets this information form Domain that holds this secret.

With one notable exception…

Shared Secrets are secrets with the name that ends with .shared.

These secrets are special in a way that they are encrypted with not only with keys belonging to recipients of a Domain that holds these secrets, but also with keys of recipients from this Domain’s subdomains.

This requires an example.

An example

Let’s say we have the following Domain hierarchy:

secrets    (allow: alice)
├── bar
│   ├── quux    (bob)  --no-inherit-recipients
│   │   └── credit-cards
│   └── secret.shared
└── baz    (jane)
    └── passwords

• secrets — root Domain

• bar — a child Domain of bar; it has a Secret called secret.shared

• quux — a child Domain of quux; it has a Secret called credit-cards; it was created with --no-inherit-recipients

• baz — another child Domain of secrets; it has a Secret called passwords

• allowed users are specified inside parenthesis

Q: So, who can decrypt secret.shared?

A: Alice and Bob can decrypt it because it’s a shared Secret. Harpo will use the following keys to encrypt it:

• Alice — because she has access to the root domain and bar inherits recipients from its parent

• Bob — because shared secrets are encrypted with keys from subdomains

Jane does NOT have access to the shared secrets.

Q: OK, how about passwords?

A: Alice and Jane. Bob has no access to this secret because it’s not shared and he only has access to his own subdomain quux

Q: And credit-cards?

A: Only Bob has access to this secret. Even though Alice has access to the root domain secrets, Harpo won’t use her key to encrpypt credit-cards because quux doesn’t inherit recipients.

Properties

Secrets don’t demonstrate any interesting properties, really.

• name — name of a Secret

Storage & Metadata

Secrets are stored as GPG encrypted files in .harpo/data/<domain_name>/<secret_name>.

Autocompletion

For Bash, add this to ~/.bashrc:

eval "$(_HARPO_COMPLETE=bash_source harpo)"

For Zsh, add this to ~/.zshrc:

eval "$(_HARPO_COMPLETE=zsh_source harpo)"

For Fish, add this to ~/.config/fish/completions/harpo.fish:

eval (env _HARPO_COMPLETE=fish_source harpo)

Open a new shell to enable completion. Or run the eval command directly in your current shell to enable it temporarily.