LibraryConsensus2017Design paperCorpus record
The ZILLIQA Technical Whitepaper
Zilliqa. The Zilliqa Team.
A 2017 design for a sharded chain: a directory service that assigns nodes, shards that process transactions in parallel, and a language proposal aimed at safe-by-construction contracts.
Zilliqa splits the network into shards that process transactions in parallel, and it uses a smaller committee to order the shards' results so the pieces form one chain.
- Evidence
- Primary paper
- Re-measured
- No
- Assumptions
- 4
- Records linked
- 5
Code
Source, repository, and what is actually hosted
- Zilliqa technical white paperhttps://docs.zilliqa.com/whitepaper.pdf
- The source URL is not a GitHub repository. No code remote is invented.
- Full text is not mirrored. Public availability is not a licence to copy the file onto this site.
- Add to a reading list
01 Claim ledger
What the paper is allowed to say
Each row is a sentence already in the study. The status is the same on every row: a model claim, not a live measurement.
Claim 01 · Paper model
Sharding is the throughput idea
If every node executes every transaction, the network is as slow as one honest node. Shards execute different sets at once. The paper's claim is that this can be done without letting a shard be captured quietly.
Claim 02 · Paper model
Proof of work is for identity, not for every block
A node performs work to join and to be assigned to a shard. That work is a sybil ticket. Day-to-day blocks inside a shard are produced by a classical Byzantine protocol, not by more hashing.
Claim 03 · Paper model
A directory committee coordinates
Someone has to assign nodes to shards, publish the shard results, and handle transactions that touch more than one shard. The paper gives this job to a committee elected from the same identity mechanism.
Claim 04 · Paper model
The smart-contract language is dataflow
Scilla, described around this design, is a language in which effects are explicit so a shard can tell what a call will touch. A general-purpose language that can touch anything does not shard cleanly.
Claim 05 · Paper model
Cross-shard is the bill
Parallelism is easy when transactions do not share state. The paper has to specify what happens when they do. That path, not the in-shard path, is where latency returns.
02 Three cuts
Observation, model, falsifier
A desk does not stop at the summary. Each claim is cut three ways, using only this study's own assumptions and checks. Nothing here is a new figure.
01 Sharding is the throughput idea
Observation
What the study says
If every node executes every transaction, the network is as slow as one honest node. Shards execute different sets at once. The paper's claim is that this can be done without letting a shard be captured quietly.
Model
What has to hold
The directory committee itself is not captured. It is a shard-sized target with a global job.
Falsifier
What would retire it
How large is a shard, and what fraction of the whole network must an attacker control to capture one?
02 Proof of work is for identity, not for every block
Observation
What the study says
A node performs work to join and to be assigned to a shard. That work is a sybil ticket. Day-to-day blocks inside a shard are produced by a classical Byzantine protocol, not by more hashing.
Model
What has to hold
Enough nodes join that each shard is large enough for its Byzantine assumption.
Falsifier
What would retire it
Can a node influence which shard it joins?
03 A directory committee coordinates
Observation
What the study says
Someone has to assign nodes to shards, publish the shard results, and handle transactions that touch more than one shard. The paper gives this job to a committee elected from the same identity mechanism.
Model
What has to hold
The directory committee itself is not captured. It is a shard-sized target with a global job.
Falsifier
What would retire it
Which transactions are allowed to touch more than one shard, and what is their latency?
04 The smart-contract language is dataflow
Observation
What the study says
Scilla, described around this design, is a language in which effects are explicit so a shard can tell what a call will touch. A general-purpose language that can touch anything does not shard cleanly.
Model
What has to hold
Enough nodes join that each shard is large enough for its Byzantine assumption.
Falsifier
What would retire it
Which transactions are allowed to touch more than one shard, and what is their latency?
05 Cross-shard is the bill
Observation
What the study says
Parallelism is easy when transactions do not share state. The paper has to specify what happens when they do. That path, not the in-shard path, is where latency returns.
Model
What has to hold
Most transactions are written so their state footprint is visible in advance.
Falsifier
What would retire it
Which transactions are allowed to touch more than one shard, and what is their latency?
03 Sequence
One action, as an operating tape
- 01A node solves a proof of work and presents it as a right to join the current epoch's committee structure.
- 02The directory service assigns the node to a shard, using the work as randomness so the node cannot cheaply choose its neighbours.
- 03Users send transactions to the shard that holds the relevant state.
- 04The shard runs a Byzantine agreement on a block of those transactions and submits the result upward.
- 05The directory committee orders shard blocks into a final chain and processes transactions that the paper marks as cross-shard.
04 Load-bearing
The argument, and where a pitch drops it
Random assignment is the security argument
The cut
A shard of a few hundred nodes is safe only if the attacker cannot choose to sit in it. The proof-of-work identity plus assignment is what makes capture require a large fraction of all identities, not a large fraction of one small group. A shard that people can pick is a small permissioned chain with extra steps.
Why it carries weight
If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.
Where it is dropped
Directory-service security dominates. If that layer is small, the shards do not add the security people infer.
Classical consensus inside the shard is a choice
The cut
Once the set is small and known, a protocol like PBFT can finalise quickly. The paper is a hybrid on purpose. Calling the whole system proof of work because join-tickets use hashes misstates where blocks come from.
Why it carries weight
If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.
Where it is dropped
Shard counts and measured throughput in a white paper are not a current benchmark.
Dataflow is how the shard knows what it is allowed to ignore
The cut
If a contract can read arbitrary state, every shard needs every state. The language restriction is not a style preference. It is the condition under which parallel execution is correct.
Why it carries weight
If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.
Where it is dropped
Shard counts and measured throughput in a white paper are not a current benchmark.
05 Register
What has to be true
Stake and threshold · Not re-measured
Enough nodes join that each shard is large enough for its Byzantine assumption.
Model · Not re-measured
The directory committee itself is not captured. It is a shard-sized target with a global job.
Model · Not re-measured
Most transactions are written so their state footprint is visible in advance.
Model · Not re-measured
Cross-shard finality is actually implemented, not left as a future optimisation.
06 Divergence
What happened after the paper
Zilliqa launched with this hybrid and later revised its roadmap toward a different architecture. Scilla remained a distinctive artefact. A current status page is not the white paper, and the white paper's sharding math should not be cited as a measurement of today's throughput.
A later client, parameter set, or reward formula is a different object. Cite this paper for the mechanism. Cite a primary release for the network. This desk has not re-run the proof.
07 Pre-mortem
What to check before you use the idea
- 0 of 4 marked on this browser. A mark is a reading note, not a pass, a rating, or a recommendation.
08 Anatomy
The paper, in the order a builder needs
The problem it names
A single committee that re-executes every transaction has a ceiling. Zilliqa's paper treats sharding as the way through that ceiling, and treats the assignment of nodes to shards as the security problem, not a configuration file.
What the design proposes
- Proof-of-work is used to identify nodes and resist Sybils, not as the final ordering of every payment.
- A directory committee coordinates shard membership. Shards run a BFT protocol on their own transaction set.
- Cross-shard effects are the hard part, and the paper's transaction model is shaped to limit them.
How the mechanism is specified
- A node proves it did work to join. The directory then places it so an attacker cannot fill a shard cheaply.
- Finality inside a shard follows the BFT vote, not the heaviest proof-of-work chain.
- The smart-contract section argues for a language that makes certain effects explicit. It is a proposal, not a guarantee about later scilla deployments.
What this page does not treat as proven
- Shard counts and measured throughput in a white paper are not a current benchmark.
- Directory-service security dominates. If that layer is small, the shards do not add the security people infer.
- The paper does not describe Zilliqa's later product history.
Why the desk still reads it
Sharding proposals still show up in venture pitches as a multiple on throughput. Zilliqa is the reminder to ask who assigns the shards and what a cross-shard call is allowed to do.
09 Lexicon
Terms, opened into the record
- Shard
- A subset of nodes that executes its own transactions and agrees internally.
- Directory service
- The committee that assigns nodes, collects shard results, and handles cross-shard work.
- Join proof of work
- Hashing used to buy an identity for an epoch, not to propose every block.
- Dataflow contract
- A programme whose effects are declared, so a scheduler can see what else it might conflict with.
10 Repository
Every linked record on this page
Underlined words open a page that already exists: a concept, a protocol profile, a failure record, or another paper. If a word is not underlined, this desk does not have a record for it.
Papers
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.