Signed Bytes Chapters Chapter 01

Series  a field guide to zkTLS

Take a proof apart, one chapter at a time.

Primus lets you prove something about a web session without handing over the session. The cryptography holds. Most of the mistakes happen in the space between a valid signature and a correct integration, and that space is where this guide lives. Every chapter carries something you operate rather than read: a real attestation you can break, a verifier you can misconfigure on purpose, a game that charges you for the check you skipped. Nothing is mocked, and nothing is promised before it is built.

the 448 bytes a signature actually covers
keccak256 → 0xcd5c9dd94cacbed8f96dcff6e217674c058e83bb53bc0af4f110fe3aeecc0659
recipient request hash response hash data attConditions timestamp additionParams
448B is everything a Primus signature actually covers in a real attestation (01) inspector 8 combinations of reserve checks tested; only all three clear every round (02) reserve desk 921 lines of the production reserve circuit, read end to end (03) the circuit 0.66s to recover a price that was committed instead of revealed (04) commitment 7/16 data sources in the extension that are actually offered (05) templates 5ms the claimed bootstrap, and the open floor measured underneath it (06) the floor

Chapters

shipped, and what is on the bench

Every chapter is something you operate rather than something you read: an instrument, a game, a set of cards. Each one is its own deployment, so it opens in a new tab. The sealed rows are real slots with nothing announced in them yet, which is the honest state of a series that follows what Primus ships.

01

The Attestation Inspector

An attestation has nine fields. Seven are hashed. The other two are the ones most integrations read first.

Paste a proof, break a field, watch the two verdicts split

  • Instrument
  • contracts and SDK
  • 2 of 9 fields unsigned

source PrimusZKTLS.sol · @primuslabs/zktls-js-sdk 0.3.14 · a real OKX attestation from the zkTLS Playground, production attestor

Read ↗
02

The reserve desk

A stablecoin publishes its backing ratio from zkTLS balance proofs. Every proof verifies. Some of them still lie.

Five rounds against a CFO who wants a better number than you can prove

  • Game
  • two live reserve deployments
  • 3 checks, all 8 combinations tested

source Brevis engineering blog, 13 April and 11 May 2026 · live dashboard for USDu

Read ↗
03

Reading the reserve circuit

The zkVM program behind the live Proof of Reserves reports is public. Two of the three checks from chapter 02 are in it. One is not.

Pick a lie, meet the line of Rust that catches it, or find out that none does

  • Reading
  • the production zkVM circuit
  • no freshness check in circuit

source primus-labs/por-client-unitas · zkvm-program/common/src/core.rs · 921 lines

Read
04

What a commitment hides

A field in a real attestation was committed with SHA256 rather than revealed. A hash hides exactly as much as the value had to begin with.

Watch your own browser recover it, then see what else would fall

  • Stopwatch
  • a real Playground attestation
  • 3 guesses, given bid and ask

source sha256("77530.4") recovered after 775,305 guesses in a blind sweep

Read
05

What it takes to make the proof

Sixteen data sources ship in the open-source extension. Three ways in, seven of them actually offered, and four request chains written out in full.

Open a template and read the endpoints and credentials each call carries

  • Cards
  • the open extension config
  • 7 of 16 sources offered

source primus-labs/primus-extension · LGPL-3.0 · Bitget commented out in commit 6b615d90, 18 September 2025

Read
06

The floor

Primus quotes a five millisecond bootstrap. The arithmetic underneath is open source, so this chapter runs its benchmarks on a named machine.

Run the same benches yourself and compare your machine with the official run

  • Benchmark
  • three CPUs, unmodified
  • 2.95× from the hardware alone

source primus-labs/primus-fhe · commit 32b316b6 · 8 July 2026 · MIT or Apache 2.0 · reported upstream as #190 and #191

Read
07 Sealed
08 Sealed
09 Sealed
10 Sealed

Where it goes next

The series is numbered and open ended. It follows what Primus actually ships rather than a table of contents written in advance, and the format follows the subject: a tool where you need to take something apart, a game where a rule only lands once it has cost you something, a set of cards where the point is to remember it afterwards.

  • Instruments. Paste something real, break a field, watch what the verifier does and does not notice.
  • Games. Play the other side. Ship an integration with a check missing and find out which attack walks through the gap you left.
  • Cards and quizzes. The short ones. Twelve cards on what a proof actually proves, answerable in a minute on a phone.

Chapters are announced when they are built, not before.

Start with chapter one

paste one, take it apart

Chapter one is not an article about the Attestation Inspector, it is the Attestation Inspector. Paste a real proof or mint one in the browser: it recomputes the digest byte for byte the way the contract does, recovers the signer from the raw hash, and draws the packed bytes at true byte width. Nine checks in two columns, and a short quiz at the end that only makes sense if you actually pressed the buttons.

Open chapter 01