Deepkey

A DNA to provide a decentralized public key infrastructure (DPKI) for keys associated with Holochain conductors and applications. Similar to centralised services like Keybase, we want users to be able to manage their "keyset" by adding and removing public/private keypairs.

See Pre-2024 Architectual Documentation for original design principles.

Overview

The keys for happs installed on a device are also tracked under the keyset for the device. A keyset is the set of keys governed by a ruleset, presumably under the control of one person.

When you install a new app in Holochain, by default a new keypair is generated to control the source chain of that app. The public key of that keypair serves as the address of your agent in that app's DHT. The private key signs all of your network communications and all actions on your chain. Deepkey registers, manages, and reports on the validity of each AgentPubKey installed on your conductor.

Why do we need Deepkey?

Because humans are notoriously bad at managing cryptographic keys, we believe a project like Holochain must provide key management tools to help people deal with real-world messiness such as lost/stolen keys or devices. How many billions of dollars have been lost due to the lack of a key management infrastructure?

Deepkey is a foundational app for all other Holochain app keys. Therefore, it is the first happ every conductor must install, and all other happs rely on it to query the status of keys. It is designed to work hand in hand with holochain's secure keystore, Lair.

The most common call to Deepkey is key_state((Key, Timestamp)) to query the validity of a key at a particular time.

Another reason is for source chain recovery

In addition to shared/public keysets and registrations, Deepkey supports private data for remembering how the keys were derived. With each key generation, the relevant "derivation details" can be saved as private entries. This private data can be used later to rebuild your keypairs and recover app source chains.

Features

Deepkey provides the ability to:

• Register keys under the authority of a keyset.
• Define the revocation rules for a keyset.
• Replace keys with new ones.
• Revoke keys / declare them dead.
• Check the validity of a key.
• Store private instructions to rebuild app keys from a master seed to reestablish authority after data loss.

Future features

• Associate multiple devices under unified keyset management.
• Do social management of keys through m of n signatures.

How it works?

Workflows

• Initializing Deepkey
• Registering a new key
• Replacing a key
• Revoking a key
• Checking key validity
• Updating the change rules

Interactions with Lair

Although Deepkey is designed to work with Lair, there is no direct dependence on Lair as all interactions with Lair are facilitated by the DPKI service in Holochain.

Lair is designed to generate new keys from randomness, or generate new keys from a seed with derivation instructions. In order to regenerate your app keys, Deepkey must store the derivation info that will instruct Lair to reproduce the same keys.

How are keys determinitic?

Key uniquenss is determined by a combination of 2 incrementing numbers; an app index and a key index. When an app is installed, a new key registration is made using the next unused app index and a key index of 0. Replacing keys will increment the key index while the app index stays the same.

Initializing Deepkey

When you install Holochain, Deepkey will create a new Keyset Root (KSR) as the first action. Then it will set the initial change rules for that KSR and register itself as the first key (ie. app/key index 0/0).

There can only be one KSR on a Deepkey source chain.

What is a KSR?

A keyset is the set of keys governed by a ruleset, presumably under the control of one person.

When you install a new app in Holochain, by default a new keypair is generated to control the source chain of that app. The public key of that keypair serves as the address of your agent in that app's DHT. The private key signs all of your network communications and all actions on your chain. Deepkey registers, manages, and reports on the validity of each AgentPubKey installed on your conductor.

A KeysetRoot (KSR) is self-declared onto the network using a single-purpose throwaway keypair.

The structure of a KeysetRoot is:

• first_deepkey_agent - (FDA) the author of the KeysetRoot.
• root_pub_key - the public part of a throwaway keypair which is only used to generate this KSR
• signed_fda - the authority of the FDA is established by signing thd FDA's pubkey using the private part of the throwaway keypair

Registering a new key

Registering a new key is a 2 step process; generating the new key outside of Deepkey and then registering it in Deepkey.

1. In order to generate the key, Deepkey provides a way to get the "next derivation details" which can be used to generate a deterministic key.
2. Then that key can be committed in Deepkey along with all the other registration input such as details about the app and derivation input.

App and derivation details are committed as private entries.

Replacing a key

Key replacement is simply a combination of key revocation and key generation committed together. It requires most of the same steps from Registering a new key and Revoking a key.

1. In order to generate the next key, Deepkey provides a way to get the "next derivation details" given a specific key which will return the existing app_index for that key and the next unsused key_index.
2. Gather the required signatures for revoking the previous key registration (see Revoking a key).
3. Then the new key can be committed as a replacement to the previous key.

Derivation details are committed as a private entry.

Revoking a key

The act of revoking a key (without a key update) ends the evolution of that key. This means that all app chains using that key will not no longer be valid as of the revocation commit timestamp.

A revocation is done by signing the KeyRegistration's ActionHash with the number of keys required by the current change rules.

Checking key validity

Using this KeyAnchor entry, the status (valid, revoked, replaced, etc.) of a key can be looked up in a single get_details call, without needing to first lookup the corresponding KeyRegistration.

This also means that any external consumer of Deepkey (other DNA's, Holochain apps, etc.) can query the key status with the core 32 bytes of the key. They do NOT need to know its registration details.

A key state can be checked using the key bytes and a timestamp. There are 3 states a key can be in

• Valid
  • the timestamp is after a key create action timestamp and before any delete action timestamps
• Invalid
  • the timestamp is before any key create action timestamps
  • or, the timestamp is after a key create action timestamp and after a delete action timestamp
• Not found
  • there are no create or delete actions

Updating the change rules

A ChangeRule defines the rules that apply to keys under the management of a keyset. It is designed to support signing with M of N keys (ie. an AuthoritySpec) which is used to validate changes to keys and the change rules themselves.

NOTE: that the spec change signature validation does NOT require that all the signers exist as agents in Deepkey. This means hardware wallets, FIDO-compliant keys, smart cards, etc. could be used to provide signatures into your multisig.

Initially, the change rule is has an AuthoritySpec set to 1 of 1 with the only authority being the FDA.

A change rule can be updated by constructing a new AuthoritySpec, signing it with the required keys (based on the existing change rule), and then commiting the new ChangeRule as an update to the original.

There can only be one ChangeRule create action on a Deepkey source chain. Any following ChangeRule commits must be udpates to the original.

Integrity Model

Documentation about the integrity validation.

See INTEGRITY_MODEL.md

Contributing

See CONTRIBUTING.md