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Glossary

Here is a comprehensive list of definitions for some common terms used in this guide.

Beacon

A Beacon represents a point of the Blockchain for which a Mithril Certificate is created. It embeds at least the version of the Cardano Network that is targeted, and the associated epoch and immutable file number.

Cardano Network

The Cardano Network is a Proof-of-Stake Blockchain platform that supports the ADA cryptocurrency.

Cardano Node

A Cardano Node is a node that runs in a Cardano Network. There are several types of nodes, among them are Cardano Full Nodes that hold a copy of the whole Blockchain. They can be used by Wallets, Stake Pool Operator, Exchanges or Dapps. One of the use cases of the Mithril Network is to bootsrap rapidly a Cardano Full Node.

Cardano Key Pair

A Cardano Key Pair is an asymmetric key pair used to identify a Stake Pool Operator on the Cardano Network.

Certificate

The Mithril Aggregator combines the produced multi signature and some metadata into a Mithril Certificate that will be later used by the Mithril Client to verify the authenticity of a snapshot. The certificates are chained so that the stake distribution used to create the signatures is verifiably genuine.

Epoch

The Cardano Network uses Epochs to group blocks computed in a certain amount of time (approximately 5 days). It is part of the design of its Proof-of-Stake consensus Ouroboros. At the end of each epoch, the stake distribution of the ending epoch is computed.

Immutable File Number

Inside a the database of a Cardano Node, the Blockchain state is stored in Immutable files which never change once committed. These immutable files are designed so that they are deterministically produced and thus are the same on any Cardano Node. These files are created by following an incremental number, the Immutable File Number and there are three different immutable files for each number (i.e. chunk, primary and secondary). Only the files up to the penultimate Immutable File Number are considered as committed and final, the last Immutable File Number files are constantly evolving. The Snapshots produced by the Mithril Network rely on these immutable files.

Individual Signature

For each Beacon, the Mithril Signers will compute on their end a message representing the Blockchain state, and sign it with their Verification Keys in order to create an Individual Signature. Upon winning one or multiple lotteries, the Mithril Signer will be able to use this Individual Signature to participate in the creation of a Multi Signature.

Mithril Aggregator

The Mithril Aggregator is a trustless node of the Mithril Network that orchestrates the work of the Mithril Signer nodes and that gathers their individual signatures to produce Mithril multi signatures and their associated certificates.

It is also in charge of creating and storing the snapshot archive.

Mithril Client

The Mithril Client node of the Mithril Network is used to restore a Cardano full node by retrieving, from a Mithril Aggregator, a remote snapshot, its certificate chain and by verifying their validity thanks to the Mithril cryptographic primitives.

Mithril Network

In its current version, the Mithril Network is a network of nodes responsible for creating Snapshots and Certificates that enable fast bootstrap of a Cardano Node. It runs on top of the Cardano Network.

Mithril Protocol

The Mithril Protocol allows stakeholders in a Proof-of-Stake Blockchain network to individually sign messages that are aggregated into a multi signature which guarantees that they represent a minimum share of the total stakes.

Mithril Signer

The Mithril Signer is a node of the Mithril Network that works transparently on top of the Stake Pool Operator Cardano nodes and which individually signs the ledger state.

Multi Signature

The Mithril Multi Signature is an aggregate of Individual Signatures which guarantees that a minimum share of the total stakes has participated in its creation.

Snapshot

A Mithril Snapshot is a signed archive of the Blockchain state that can be used by Mithril Clients to restore a Cardano Full Node. It is uniquely identified by its fingerprint or Digest which is part of the message signed by the Mithril Network.

Stake Distribution

The Cardano Stake Distribution is the list of all the Stake Pool Operators Pool Id addresses and their associated Stakes Share of the total Stakes of the Cardano Network.

The Mithril Stake Distribution is the list of all the Stake Pool Operators (that are running a Mithril Signer) Pool Id addresses, their associated Stakes Share of the total Stakes of the Cardano Network, and their signing Verification Key.

Stake Pool Operator (SPO)

A Stake Pool Operator, also known as a SPO, represents a party that holds (via delegation) Stakes in the Cardano Network. The stakes entitle it to participate in the block production thanks to the Cardano consensus mechanism.

Verification Key

In order to create Individual Signatures, the Mithril Signers must register their signing public key: the Verification Keys. To garantee their genuineness, they are signed by the associated Cardano Key Pair. It is worth mentioning that a Mithril Signer must be aware of the Verification Keys of all the other Mithril Signers in order to produce valid Individual Signatures.

Glossary

Beacon​

Cardano Network​

Cardano Node​

Cardano Key Pair​

Certificate​

Epoch​

Immutable File Number​

Individual Signature​

Mithril Aggregator​

Mithril Client​

Mithril Network​

Mithril Protocol​

Mithril Signer​

Multi Signature​

Snapshot​

Stake Distribution​

Stake Pool Operator (SPO)​

Verification Key​