> ## Documentation Index
> Fetch the complete documentation index at: https://docs.coinlotto.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Fairness and Transparency

<Warning>
  This page is a Draft. Its content may change before final publication.
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Trust is built into the protocol through on-chain lottery activity, immutable smart contracts, public verification, and verifiable randomness.

Ticket purchases, Prize Pool changes, draws, and claims are recorded on-chain and can be independently inspected.

## Fully on-chain

CoinLotto is a fully on-chain protocol. Smart contracts execute and record all core product logic, including:

* lottery creation and fixed configuration;
* ticket purchases and ticket-number assignment;
* Prize Pool accounting, Prize Pool Top-Ups, fees, and Super Lottery allocations;
* permanent referral binding and referral-reward availability;
* Mission progress;
* draw availability, execution, winner selection, and finalization;
* prize, reward, and fee claims.

The CoinLotto interface is an access point to the protocol, not its source of truth. No off-chain backend, database, manual approval, or operator determines or can change these outcomes.

## Verifiable randomness

CoinLotto uses **Chainlink VRF 2.5**, an independent third-party verifiable-randomness service, for lottery winner selection.

Each request, cryptographic proof, and final result can be verified on-chain. No CoinLotto operator, Creator, or participant can choose, replace, or alter the random value used for a completed draw.

See [Verifiable Randomness](/trust-and-security/verifiable-randomness) for the Chainlink VRF flow, retry conditions, and independent draw verification.

## Non-custodial Prize Pools

Each Prize Pool is held by immutable smart contracts, not by CoinLotto, a Creator, or a third-party custodian.

Funds can move only under the lottery’s encoded rules. Neither CoinLotto nor a Creator can manually withdraw, reassign, or transfer a Prize Pool.

## Independent audit

See [Audit & Contract Verification](/trust-and-security/audit-and-contract-verification) for the current status of the **CertiK** audit and available materials.

## Immutable smart contracts

All CoinLotto smart contracts are immutable. They cannot be upgraded or modified.

## Lottery rule integrity

Every CoinLotto lottery is created with a fixed configuration. Once live, its rules cannot be changed and its parameters remain publicly verifiable on-chain.

## Protocol change transparency

Some protocol configuration parameters may be updated (for example, the maximum lottery duration, the permitted minimum and maximum values for the Multiplier and Win Rate models, and the maximum number of prize tiers).

Any update applies only to newly created lotteries. Such updates never alter an active lottery, its rules, or its Prize Pool. Existing lotteries retain the fixed configuration set when they were created, and that configuration cannot be changed.

When a change affects users, CoinLotto publishes it in the **Changelog** and **Discord** before it takes effect. Each notice states the current value, user impact, and effective date.

## Sanctions screening

CoinLotto uses the [Chainalysis Oracle ↗](https://go.chainalysis.com/chainalysis-oracle-docs.html) to screen wallet addresses against applicable sanctions data under the protocol’s rules.

## Verify on-chain

Users do not need to rely solely on the CoinLotto interface. On supported blockchain explorers, users can verify lottery transactions and contract state directly.

## Related Pages

* [Lottery Draw](/lottery-mechanics/lottery-draw)
* [Verifiable Randomness](/trust-and-security/verifiable-randomness)
* [Claiming Rewards](/lottery-mechanics/claiming-rewards)
* [Audit & Contract Verification](/trust-and-security/audit-and-contract-verification)
* [Supported Networks](/reference/supported-networks)
* [Supported Tokens](/reference/supported-tokens)


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