Glossary

This glossary defines key terms used throughout the Walrus documentation, covering storage concepts, erasure coding, cryptographic primitives, token economics, and network roles.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Aggregator

Service that reconstructs blobs by interacting with storage nodes and exposes a basic `HTTP GET` endpoint to end users.

Availability period

The period specified in storage epochs for which a blob is certified to be available on Walrus.

B

Blob

Single unstructured data object stored on Walrus.

Blob ID

Cryptographic ID computed from a blob's slivers.

Blob metadata

Metadata of one blob; in particular, this contains a hash per shard to enable the authentication of slivers and recovery symbols.

C

Cache

An aggregator with additional caching capabilities.

Certificate of availability

A blob ID with signatures of storage nodes holding at least \(2f+1\) shards in a specific epoch.

Client

Entity interacting directly with the storage nodes; this can be an aggregator or cache, a publisher, or an end user.

D

Deletable blob

Blob that can be deleted by its owner at any time to reuse the storage resource.

E

Expiry

The end epoch at which a blob is no longer available and can be deleted; the end epoch is always exclusive.

F

FROST

The smallest unit of WAL (similar to MIST for SUI); 1 WAL is equal to 1 billion (1000000000) FROST.

I

Inconsistency certificate

An aggregated signature from 2/3 of storage nodes (weighted by their number of shards) that they have seen and stored an inconsistency proof for a blob ID.

Inconsistency proof

Set of several recovery symbols with their Merkle proofs such that the decoded sliver does not match the corresponding hash; this proves an incorrect/inconsistent encoding by the client.

M

Member

A storage node that is part of a committee at some epoch.

P

Permanent blob

Blob that cannot be deleted by its owner and is guaranteed to be available until at least its expiry epoch (assuming it is valid).

Point of availability

Point in time when a certificate of availability is submitted to Sui and the corresponding blob is guaranteed to be available until its expiration.

Publisher

Service interacting with Sui and the storage nodes to store blobs on Walrus; offers a basic `HTTP POST` endpoint to end users.

R

Reconstruction

Decoding of the primary slivers to obtain the blob; includes re-encoding the blob and checking the Merkle proofs.

RedStuff

Erasure-encoding approach, which uses two different encodings (primary and secondary) to enable shard recovery; details are available in the [whitepaper](./walrus.pdf).

S

Shard

(Disjoint) Subset of erasure-encoded data of all blobs; at every point in time, a shard is assigned to and stored on a single storage node.

Shard recovery

Process of a storage node recovering a sliver or full shard by obtaining recovery symbols from other storage nodes.

Sliver

Erasure-encoded data of one shard corresponding to a single blob for one of the two encodings; this contains several erasure-encoded symbols of that blob but not the blob metadata.

Sliver pair

The combination of a shard's primary and secondary sliver.

Storage attestation

Process where storage nodes exchange challenges and responses to demonstrate that they are storing their currently assigned shards.

Storage committee

The set of storage nodes for a storage epoch, including metadata about the shards they are responsible for and other metadata.

Storage epoch

The epoch for Walrus as distinct to the epoch for Sui.

Storage node

Entity storing data for Walrus; holds one or several *shards*.

U

User

Any entity or person that wants to store or read blobs on or from Walrus; can act as a Walrus client itself or use the simple interface exposed by publishers and caches.

W

WAL

The native token of Walrus.