Provably Fair System For Infinite Packs

Last Updated: 1 July, 2026

Infinite Packs are designed to be opened without limit. There is no fixed number of openings and no “session” that ends. OpenHype is the first to bring a provably fair system to digital trading card pack openings (Gacha Packs), and this document walks through the full lifecycle of that mechanism: what happens before an opening, what happens at the moment of an opening, and how you can prove afterward that every result was honest.

Core Principle

In Infinite Packs, every opening produces a number, your Roll, and that number determines the card you receive. The entire point of “provably fair” is to guarantee that this number is determined by a set of inputs that neither you nor OpenHype can tamper with after the result is revealed.

We achieve this by combining the following inputs:

A Server Seed, locked in before you open by publishing its Public Hash.
A Client Seed, fully controlled by you and changeable at any time.
A Nonce, a counter that increments with every opening.

Because the Server Seed is locked in via the Public Hash before you open, we cannot swap it out afterward to give you a worse result. And because the Client Seed is controlled by you, we cannot pre-select a Server Seed that pairs poorly with yours. The final result is mathematically sealed before it happens and fully auditable afterward.

Account-Level Seed Mechanism

In Infinite Packs, your Server Seed is bound to your account. Since you may open a large number of packs in succession, each Server Seed is designed to be reused, with the Nonce guaranteeing the uniqueness of every result.

Here is how it works in practice:

When you begin, OpenHype generates a Server Seed for your account, together with its own dedicated Secret Salt, and immediately publishes its Public Hash to your fairness panel. This is our binding commitment, proof that the Server Seed existed and was fixed before you drew any card.
Every opening you perform uses the currently active Server Seed.
The Nonce increments by exactly +1 with each opening, so that even with an unchanged Server Seed, every result is different.
Each Server Seed automatically resets after 500 uses. When the Nonce reaches 500, the current Server Seed is revealed, and the system generates a new Server Seed, with a new dedicated Secret Salt, and publishes its Public Hash.
Once a Server Seed is reset and revealed, every opening made under it becomes 100% verifiable.

So at any given moment, your currently active Server Seed keeps your future openings unpredictable. Neither party can foresee them. OpenHype cannot predict them because you can change your Client Seed at any time, and you cannot predict them because you do not know the active Server Seed. Meanwhile, every revealed Server Seed lets you audit your past openings, so you can prove them.

Glossary

Server Seed: A secret string generated by OpenHype and assigned to your account. It stays hidden while active, but its Public Hash is published in advance. The Server Seed itself is fully revealed when it resets.

Client Seed: A string that you own and can rewrite at any time. Changing it produces a completely different sequence of results from that point on, which is your proof that we never designed a Server Seed around your specific Client Seed.

Nonce: A counter bound to the currently active Server Seed. It increments by +1 with each opening, allowing the same Server Seed and Client Seed to generate non-repeating Rolls until the reset limit of 500 is reached.

Secret Salt: A specific string that is unique to each Server Seed, used to protect that Server Seed so that it cannot be decoded by users, and consequently used while generating that Server Seed's Public Hash. Each Server Seed has its own dedicated Salt, which is revealed together with the Server Seed when it resets.

Public Hash: A string of the form hash(server seed + salt) that is always available to users and guarantees that the Server Seed has been unchanged. It is computed as:

Roll: The verifiable random number used to select your card.

Odds Range: The complete, publicly published mapping of reward tiers, listing each tier and its corresponding winning interval.

Step by Step: How an Opening Is Generated

When you open an Infinite Pack, here is exactly what happens behind the scenes, with nothing hidden:

Step 1: Build the intermediate key.

Compute HMAC-SHA512, where the message is the Server Seed and the key is the Client Seed concatenated with the current Nonce using a hyphen, in the format clientSeed-nonce:

The output is a long hexadecimal string.

Step 2: Truncate.

Take the first 15 hexadecimal characters of , denoted .

Step 3: Convert and take the modulo.

Convert these 15 hex characters into a decimal integer, then take it modulo the pack's MaxRollNumber (100,000 for Infinite Packs).

Step 4: Offset.

Add 1 to obtain the final Roll. Steps 3 and 4 combined:

The final Roll ranges from 1 to 100,000.

Step 5: Map to a card.

Compare the Roll against the published Odds Range to locate the corresponding reward tier. Each Odds Range maps to a card tier containing multiple cards, and the system randomly delivers one card from that tier to you.

Step 6: Increment.

The Nonce increments by +1, ready for your next opening.

Every step is deterministic. Identical inputs always produce an identical Roll, and that is precisely what makes independent verification possible.

Why Incrementing the Nonce Preserves Randomness

It is natural to wonder how changing a single digit in the Nonce can produce a genuinely random new result. The answer is the avalanche effect, a core property of cryptographic hash functions: changing even a single character in the input completely scrambles the output, with no traceable relationship to the change that was made.

Two inputs that differ only in their final digit, clientSeed-1 and clientSeed-2, produce results that appear entirely unrelated. There is no pattern to follow and no trend to exploit, which is exactly why a single account-level Server Seed can drive a large number of Rolls that are both unpredictable and provable.

Why the Secret Salt Makes Cheating Impossible

The Secret Salt is a crucial part of the mechanism, and it provides protection in two directions at once. Note that each Server Seed has its own dedicated Salt, so revealing one Server Seed's Salt never weakens the protection on any other Server Seed.

First, it prevents you from decoding the Public Hash.

If the Public Hash were simply hash(server seed), someone could in theory reverse-engineer the Server Seed through precomputation or brute force and calculate all future Rolls in advance. But because we use the Secret Salt as the HMAC key, and that Salt is kept secret from users while the Server Seed is active, no one can recompute the Public Hash to test a guess at the Server Seed without knowing the Salt. The Public Hash is therefore a true one-way lock.

Second, it cannot be used by us to cheat either.

You might ask: since the Salt is held privately by us, could we change the Salt after the fact to cover up a tampered Server Seed? The answer is no. Suppose we wanted to secretly swap the Server Seed, after you open, for a that favors the platform. Since the Public Hash was published and fixed long before you opened, making this forged seed pass verification would require us to find some such that:

This is essentially a preimage attack: recovering the key given a fixed output and a fixed message. For SHA-256 this is computationally infeasible, and the required computing power is astronomical. So even though the Salt is under our control, we cannot use it to make a tampered Server Seed match the Public Hash we committed to in advance. Once the commitment is published, it is sealed.

How to Verify Your Openings

The Provably Fair panel in your account provides everything you need:

The Public Hash of the currently active Server Seed.
Your Client Seed, editable at any time.
The complete history of your revealed Server Seeds (each revealed together with its own dedicated Secret Salt).
A Roll ID on every opening, revealing the exact inputs and computation behind that result.

For each card drawn from an Infinite Pack, you can check the randomness behind how that card was drawn using the provably fair mechanism.

Verifying a revealed Server Seed:

Once a Server Seed is reset and revealed, you can recompute its Public Hash yourself using any standard HMAC tool. The message is the revealed Server Seed, the key is that Server Seed's own Secret Salt, and the algorithm is SHA-256. If the result matches the Public Hash we published before you opened, it proves the Server Seed was never changed.

Verifying a specific Roll:

Using the revealed Server Seed, your Client Seed, and the Nonce of that opening, recompute Steps 1 through 4 above. The Roll you reproduce must match exactly the one you received. If anything fails to match, fairness has been broken, and you hold cryptographic proof of it.

When and How a Server Seed Resets

You are never locked into a Server Seed you do not accept. The current Server Seed resets under either of the following conditions:

Automatic reset: When the Nonce reaches 500. The current Server Seed is fully revealed, and the system generates a new Server Seed, with a new dedicated Secret Salt, and immediately publishes its Public Hash.
Choosing to reveal the current Server Seed: You may choose to reveal the current Server Seed at any time. You never have to wait until 500. Once revealed, it resets and the system replaces it with a new Server Seed and a new dedicated Secret Salt.

In either case, the moment the Server Seed resets it is fully revealed, and every opening made under it can be verified end to end. You then begin a fresh cycle with a new, committed Server Seed.

Our Commitment to Transparency

We believe a guarantee only counts if you can see it and check it for yourself. That is why everything that shapes your result is public: every reward tier and its exact Odds Range, the cards contained in each tier, and the full history of your revealed Server Seeds and their Salts. Nothing about how a card is drawn is hidden behind closed doors, and you can verify any opening with the provably fair mechanism at any time, not just when something looks off, but whenever you want.