Skip to content

LibraryScaling2018Design paperCorpus record

OmniLedger: A Secure, Scale-Out, Decentralized Ledger via Sharding

OmniLedger. Eleftherios Kokoris-Kogias, Philipp Jovanovic, Linus Gasser, Nicolas Gailly, Ewa Syta and Bryan Ford.

OmniLedger reassigns validators to shards, uses a bias-resistant randomness beacon, and atomically commits cross-shard transactions.

A reading of the public paper. Not a copy, not a benchmark, and not a claim about any later network.

When a pitch says sharded, ask who assigns the committee and what happens to a transaction that touches two shards.

The five-minute read

The defect

A sharded ledger that lets an adversary land in one shard has not sharded the security. It has concentrated it.

The proposal

OmniLedger reassigns validators to shards, uses a bias-resistant randomness beacon, and atomically commits cross-shard transactions.

Shard assignment is the security question.

Cross-shard transactions must commit or abort together.

The bound

The paper is not a deployed chain's validator count.

One action, walked through

  1. Elect a shard assignment from randomness the adversary cannot grind after seeing it.
  2. Process a transaction inside the shard committee.
  3. If it touches another shard, run the atomic path the paper specifies.
  4. What is atomic across shards?

The argument, unpacked

What the paper is for

When a pitch says sharded, ask who assigns the committee and what happens to a transaction that touches two shards.

What happened after

Elastico and RapidChain are the neighbouring papers. Production shards copied pieces and dropped others.

What has to be true

  • The paper is not a deployed chain's validator count.
  • Randomness and committee size are assumptions.
  • A cross-shard path that is only a bridge with an admin key is a different design.

What happened after the paper

Elastico and RapidChain are the neighbouring papers. Production shards copied pieces and dropped others.

What to check before you use the idea

  • Who samples the shard?
  • What is atomic across shards?
  • What fraction of a committee can be Byzantine?

Terms

Shard
A committee and a state that do not see every transaction.
Atomic commit
All shards involved accept the transaction, or none do.

The problem the paper names

A sharded ledger that lets an adversary land in one shard has not sharded the security. It has concentrated it.

What the design proposes

  • Shard assignment is the security question.
  • Cross-shard transactions must commit or abort together.
  • A client should not have to trust one shard's word against the ledger.

How the mechanism is specified

  • Elect a shard assignment from randomness the adversary cannot grind after seeing it.
  • Process a transaction inside the shard committee.
  • If it touches another shard, run the atomic path the paper specifies.

What this page does not treat as proven

  • The paper is not a deployed chain's validator count.
  • Randomness and committee size are assumptions.
  • A cross-shard path that is only a bridge with an admin key is a different design.

Why a venture studio still reads it

When a pitch says sharded, ask who assigns the committee and what happens to a transaction that touches two shards.

This is Blockchain Lab's reading of a public design paper. It is not the paper, not a copy of it, and not an offer of tokens, equity, custody or a partnership. Later network behaviour can diverge from the text. Nothing here is investment, legal or technical advice.

Research status: Design paper. Last reviewed: 1 October 2026. This is a reading of a public paper, not investment, legal or security advice.