Series 01 · Field Instruments · fairness lab

Rip it open. Then check the maths.

Every Packrip pack is committed before it exists and sealed by a live Solana mainnet blockhash nobody could know in advance. Five cards fall out, and anyone, anywhere, can re-derive every one of them.

Step through a rip

Sample set, free to rip. Nothing is sold or shipped.

Current slot—
Latest finalized blockhash · the next seal
Packs ripped here0
01

The rip bench

Rip one pack by hand, one step at a time. Each step does real cryptography in your browser and real reads from Solana mainnet; nothing is simulated.

  1. 1

    Commit

    ready

    Your browser draws a 32-byte secret seed and publishes only its SHA-256 hash. The seed cannot change after this without the hash showing it.

  2. 2

    Anchor optional

    optional

    Write the commitment into a mainnet transaction with the SPL Memo program, signed by your own wallet. It timestamps the commit on-chain before the seal exists. Costs one network fee; sends nothing to anyone.

  3. 3

    Seal

    waiting

    Only now is the latest finalized blockhash read from mainnet. It did not exist when you committed, so neither you nor the site could have steered it.

  4. 4

    Rip and reveal

    waiting

    Each card is HMAC-SHA-256(seed, blockhash : client seed : nonce : card). The first 52 bits pick the tier against the published odds; the next 32 pick the item within it. Then the seed is revealed.

02

Inside the seal

  1. 32 random bytes become the seed.
  2. SHA-256 folds them into the commitment you can publish.
  3. A mainnet blockhash arrives that no one chose.
  4. HMAC mixes seed and blockhash into a roll for every card.
  5. The roll lands on the odds table. The card is fixed.
03

Verify any rip

Paste a receipt, or use the last rip. The verifier recomputes the commitment, re-derives all five cards, and asks Solana mainnet whether that blockhash really belongs to that slot.

04

Odds and the rarity chart

The table every rip is decided against. Then test it: rip thousands of packs with fresh random seeds using the exact same HMAC derivation, and compare what fell out with what was promised.

Tier odds per card
Bars: published odds per card. Run the simulation to overlay observed rates.
05

Expected-value calculator

Put a price on the pack and a value on each tier. The calculator gives the exact expected value, its spread, and the chances you actually care about. The value distribution is a labelled simulation.

Simulation: 20,000 packs drawn from the odds table. Dashed line: pack price.
06

Your binder

Connect a wallet and every rip uses your address as the client seed, so your pulls are bound to you. They are filed here under your address; sign the binder to prove it, or print a receipt anyone can verify.

No pulls yet. Rip a pack above.

07

How fair is fair

Commit first

The hash goes out before the seal is known. A seed swapped later would produce a different hash, and the verifier catches it in one line.

Seal with the chain

A finalized Solana blockhash is produced by the network's leaders, not by Packrip. It is unpredictable before it exists and permanent after.

Derive, don't draw

Cards are a pure function of seed, blockhash, client seed and nonce. Same inputs, same cards, on any machine, forever.

Check the table

The odds are public and the simulation lets you test them. If a tier came out more or less often than promised over thousands of rips, the chi-square test would flag it.

08

What is real here

Real: the seed, SHA-256 commitment and HMAC derivation (Web Crypto in your browser); the blockhash and slot (live from Solana mainnet); the on-chain verification (getBlock); your SOL balance; the optional Memo anchor, which is a real mainnet transaction you sign yourself.

Sample: Series 01 and its 24 items are an illustrative set drawn in code. Nothing is sold, shipped, minted or held, and pulls have no cash value.

Model and simulation: tier values in the EV calculator are yours to set; the value histogram and the odds simulation are labelled simulations.

Trust note: in this lab the seed is generated in your own browser, so you are both house and player. A real pack service would run the same protocol with the house holding the seed; the commitment and the blockhash seal are what would keep it honest.

09

FAQ

Why a blockhash and not my own random number?

Because whoever picks the randomness could pick it after seeing the result. A finalized blockhash read after the commitment is outside both parties' control.

How does the verifier know the blockhash is real?

It calls getBlock for the recorded slot on Solana mainnet and compares the returned blockhash with the receipt. Anyone can run the same call with any RPC provider.

What is the client seed for?

It lets the person ripping add their own input. When your wallet is connected it is your address, which binds the pulls to you; you can also type anything.

Does anchoring cost anything?

One Solana network fee, usually 5,000 lamports (0.000005 SOL). The memo transaction moves no SOL or tokens. It is optional: the blockhash seal alone is enough for the derivation.

Is this a shop?

No. Packrip is a fairness lab and a sample set. There is nothing to buy, and nothing you rip has value.

Can odds be checked from outside the site?

Yes. The receipt holds every input; the derivation is written out on this page. A dozen lines in any language with HMAC-SHA-256 will reproduce every card.