Pocket Protector 🔏

Pocket Protector provides a cryptographically-strong, serverless secret management infrastructure. Pocket Protector enables key management as code, securely storing secrets in a versionable format, right alongside the corresponding application code.

Pocket Protector's approach lets you:

• Leverage existing user, versioning, and backup systems, with no infrastructure to set up
• Support multiple environments
• Integrate easily with existing key management systems (AWS/Heroku/TravisCI)

Pocket Protector also:

• Minimizes the number of passphrases and keys your team has to remember and secure
• Beats the heck out of hardcoded plaintext secrets!

Installation

Right now the easiest way to install Pocket Protector across all platforms is with pip:

pip install pocket_protector

This will install the command-line application pocket_protector, conveniently shortened to pprotect, which you can use to test your installation:

$ pprotect version
pocket_protector version 18.0.1

Once the above is working, we're ready to start using Pocket Protector!

Usage

Pocket Protector aims to be as easy to use as a secret management system can get. That said, understanding security takes time, so be sure to go beyond the quick start and reference below, and read our User Guide as well.

Quick start

Pocket Protector's CLI is its primary interface. It presents a compact set of commands, each representing one action you might want to take on a secret store. Basic usage starts on your laptop, inside your checked out code repository:

# create a new protected file
pprotect init

# add a key domain
pprotect add-domain

# add a secret to the new key domain
pprotect add-secret

# decrypt and read out the secret
pprotect decrypt-domain

Each of these will prompt the user for credentials when necessary. See the section below on passing credentials.

When you're done updating the secret store, simply git commit (or equivalent) to save your changes. Should you make any mistakes, use your VCS to revert the changes.

Passing credentials

By default, the pocket_protector command prompts you for credentials when necessary. But convenience and automation both demand more options, highlighted here:

• Command-line Flags

  • -u / --user USER_EMAIL - specifies the user email for subcommands which require it
  • --passphrase-file PATH - specifies a path to a readable file which contains the passphrase (useful for mount-based key management, like Docker)
  • --domain DOMAIN - specifies the name of the domain
  • --non-interactive - causes the command to fail when credentials cannot be gotten by other means

• Environment variables

  • PPROTECT_USER - environment variable which contains the user email
  • PPROTECT_PASSPHRASE - environment variable which contains the passphrase (useful for environment variable-based key management, used by AWS/Heroku/many CI systems)

In all cases, flags take precedence over environment variables, and both take precedence over and bypass interactive prompts. In the event an incorrect credential is passed, pocket_protector does not automatically check other sources.

See our User Guide for more usage tips.

Command summary

Here is a summary of all commands:

usage: pprotect [COMMANDS]

Commands:
  add-domain            add a new domain to the protected
  add-key-custodian     add a new key custodian to the protected
  add-owner             add a key custodian as owner of a domain
  add-secret            add a secret to a specified domain
  decrypt-domain        decrypt and display JSON-formatted cleartext for a
                        domain
  init                  create a new pocket-protected file
  list-all-secrets      display all secrets, with a list of domains the key is
                        present in
  list-audit-log        display a chronological list of audit log entries
                        representing file activity
  list-domain-secrets   display a list of secrets under a specific domain
  list-domains          display a list of available domains
  list-user-secrets     similar to list-all-secrets, but filtered by a given
                        user
  rm-domain             remove a domain from the protected
  rm-owner              remove an owner's privileges on a specified domain
  rm-secret             remove a secret from a specified domain
  rotate-domain-keys    rotate the internal keys for a particular domain (must
                        be owner)
  set-key-custodian-passphrase
                        change a key custodian passphrase
  update-secret         update an existing secret in a specified domain

Design

The theory of operation is that the protected.yaml file consists of "key domains" at the root level. Each domain stores data encrypted by a keypair. The public key of the keypair is stored in plaintext, so that anyone may encrypt and add a new secret. The private key is encrypted with the owner's passphrase. The owners are known as "key custodians", and their private keys are protected by passphrases.

Secrets are broken up into domains for the purposes of granting security differently. For example, prod, dev, and stage may all be different domains. Protected stores may have as few or as many domains as the team and application require.

To allow secrets to be accessed in a certain environment, Pocket Protector must be invoked with a user and passphrase. As long as the credentials are correct and the user has permissions to a domain, all secrets within that domain are unlocked.

Passphrase security will depend on the domain. For instance, a domain used for local development may set the passphrase as an environment variable, or hardcode it in a configuration file.

On the other hand, a production domain would likely require manual entry of an authorized release engineer, or use AWS/GCP/Heroku key management solutions to inject the passphrase.

for prod domains, use AWS / heroku key management to store the passphrase

An application / script wants to get its secrets:

# at initialization
secrets = KeyFile.decrypt_domain(domain_name, Creds(name, passphrase))
# ... later to access a secret
secrets[secret_name]

An application / script that wants to add / overwrite a secret:

KeyFile.from_file(path).with_secret(
    domain_name, secret_name, value).write()

Note -- the secure environment key is needed to read secrets, but not write them. Change management on secrets is intended to follow normal source-code management.

File structure:

[key-domain]:
  meta:
    owners:
      [name]: [encrypted-private-key]
    public_key: [b64-bytes]
    private_key: [b64-bytes]
  secret-[name]: [b64-bytes]
key-custodians:
  [name]:
    public-key: [b64-bytes]
    encrypted-private-key: [b64-bytes]

Threat model

An attacker is presumed to be able to read but not write the contents of protected.yaml. This could happen because a developer's laptop is compromised, GitHub credentials are compromised, or (most likely) Git history is accidentally pushed to a publicly acessible repo.

With read access, an attacker gets environment and secret names, and which secrets are used in which environments.

Neither the file as a whole nor individual entries are signed, since the security model assumes an attacker does not have write access.

Notes

Pocket Protector is a streamlined, people-centric secret management system, custom built to work with distributed version control systems.

• Pocket Protector is a data protection tool, not a change management tool. While it has convenient affordances like an informal audit_log, Pocket Protector is meant to be used in conjunction with your version management tool. Signed commits are a particularly good complement.
• Pocket Protector is designed for single-user usage. This is not a scaling limitation as much as it is a scaling feature. Single-user means that every pprotect command needs at most one credentialed user present. No sideband communication is required, minimizing leakage, while maintaining a system as distributed as your version management.

FAQ

Securing Write Access

Pocket Protector does not provide any security against unauthorized writes to the protected.yaml file, by design. Firstly, without any Public Key Infrastructure, Pocket Protector is not a good basis for cryptographic signatures. (An attacker that modifies the file could also replace the signing keypair with their own; the only way to detect this would be to have a data-store outside of the file.)

Secondly -- and more importantly -- the Git or Mercurial repository already has good controls around write access. All changes are auditable, authenticated with ssh keypairs or user passphrases. For futher security, consider using signed commits:

• https://git-scm.com/book/id/v2/Git-Tools-Signing-Your-Work
• https://help.github.com/articles/signing-commits-using-gpg/
• https://docs.gitlab.com/ee/user/project/repository/gpg_signed_commits/index.html