# keyfork # An opinionated and modular toolchain for generating and managing a wide range of cryptographic keys offline and on smartcards from a shared bip39 mnemonic phrase. Keyfork can be used by organizations and solo users, for the purposes of disaster recovery, cold storage, and reproducibility of private keys and secret data. Keyfork achieves this by using a bip32 seed loaded into an agent to generate deterministic and unique keypairs. This ensures only the agent has control over the mnemonic itself, and other components can request deterministic data. The seed can be split using the Keyfork Shard mechanism, which utilizes Shamir's Secret Sharing to allow "M-of-N" recovery of the seed. This repository must not be managed by `cargo-hakari`, to ensure each plumbing binary can be built with as few dependencies and SLOC to review as possible. ## Dependency Policy Dependencies must not be added to core utilities such as seed generation and path derivation without a _really_ good reason we can't implement it ourselves, such as cryptography libraries. For instance, `keyfork-derive-util` _only_ utilizes cryptography libraries, `serde`, and `thiserror`, with the latter two being audited dependencies. Utilities such as forklets (applications that use derived data, such as an OpenPGP keychain generator) and the kitchen-sink `keyfork` utility may pull in additional dependencies _as needed_, but should strive to use the standard library as much as possible. To avoid code reuse, additional crates (such as the `smex` crate) may be used to share functionality across several crates. ## Keyfork Top-Level Binary The `keyfork` binary is the most user-friendly interface for interacting with the Keyfork toolchain. It offers commands that are intended to accept human-readable input and produce human-readable output, and can be described as a "Terminal User Interface" rather than a "Command Line Interface". An example of a `keyfork` command would be `keyfork wizard generate-shard-secret`, which will generate a secret, provision smart cards, and export the newly-generated Shard file. Processes included in the `keyfork` binary should not accept arbitrary strings or numbers, such as manual derivation paths, and instead should ask for values like "account index" and generate their own magic values if necessary. --- Note: The following features are proposed, and may not yet be implemented. ## Features * Modular * Standalone binaries can derive/manage keys/config * Modules handle use cases like ssh, pgp, webauthn, crypto-assets, etc * Module contract is dead simple and can be written in any language * Recoverable * Config file and 24 word mnemonic phrase to recover *every* key * Shard mechanism allows for "M-of-N" recovery of seed if lost * Unpredictable * Generate a BIP39 phrase from OS or physicalized entropy * Provide and use BIP39 passphrase from user supplied entropy * Read up on [https://milksad.info](milksad) to understand why this matters! * Deterministic * Given the same seed, repeated derivation requests will be reproducible * Any secret data can be derived again at any point in the future * Offline * Will exit if network access is detected to force you to keep keys offline * Helps limit the risk of supply chain attacks * Intended for use with QubesOS Vault VM, AirgapOS, etc * Private keys are installed to HSMs/TEEs for use by online machines ## Install These steps will allow you to prove that at least two Distrust engineers signed off on the produced binaries, signaling that they reproduced them from source code and got identical results, in addition to our usual two-party code review processes. This minimizes a single point of trust (and failure) in our binary release process. See the [Reproducible Builds](https://reproducible-builds.org/) project for more information on these practices. We use git for all development, releases, and signing. Unfortunately git has no native method for large file storage or multi-signature workflows so some git add-ons are required. To follow these steps please install [git-lfs][gl] and [git-sig][gs]. [gs]: https://git.distrust.co/public/git-sig [gl]: https://git-lfs.com 1. Clone repo ```sh git clone https://git.distrust.co/public/keyfork cd keyfork ``` 2. Review binary signatures ```sh git sig verify ``` Note: See Trust section below for expected keys/signers 3. Install binary ``` make install ``` ## Basic Usage ### Personal Setup On an airgapped system, run the following command to generate a BIP-0039 mnemonic encoding a generated seed: ```sh keyfork mnemonic generate ``` Once generated, the mnemonic should be written down and stored in a secure location such as a safe. The Keyfork server can be started by running the following command: ```sh keyfork recover mnemonic ``` ### Group Setup This guide assumes you are sharding to an `N`-of-`M` system with `I` smart cards per shardholder. The variables will be used in the following commands as `$N`, `$M`, and `$I`. The smart cards will be factory reset during the process. On an airgapped system, run the following command to generate a file containing encrypted shards of a generated seed: ```sh keyfork wizard generate-shard-secret --threshold $N --max $M --keys-per-shard $I --output shards.pgp ``` Once generated, the shards file can be safely stored in any location, as the only information that can be obtained from the shard file is the `$N` value. If all shardholders are physically present, the Keyfork server can be started by running the following command: ```sh keyfork recover shard ``` Otherwise, the Keyfork server can be started by transporting the shards to the machine using the following command: ```sh keyfork recover remote-shard ``` Each shard can be transported by running the following command: ```sh keyfork shard transport shard.pgp ``` ### Deriving Keys Keys can be derived from Keyfork using the `keyfork derive` command, such as the following command for an OpenPGP certificate with one of each subkey: ```sh keyfork derive openpgp "Ryan Heywood (RyanSquared) " ``` ## Usage Detailed usage instructions can be found in the [`keyfork-user-guide`] mdBook, which can be opened in-browser by running `mdbook serve --open keyfork-user-guide`. [`keyfork-user-guide`]: /public/keyfork/src/branch/main/keyfork-user-guide/src/SUMMARY.md