# commit_reveal_period (/docs/hyperparameters/commit-reveal-period)

`commit_reveal_period` (on chain: `RevealPeriodEpochs`) is how long committed
weights stay hidden before they are revealed, measured in **epochs (tempos),
not blocks**. With the default of 1 and a 360-block tempo, weights committed
in one epoch become public roughly one tempo (\~72 minutes) later. Subnet
owners tune it to balance copy-resistance (longer hiding) against how stale
weights are when they finally land.

## How it works [#how-it-works]

Each commit is tagged with the subnet's current epoch index. The reveal is
valid in **exactly one epoch**: `is_reveal_block_range`
(`pallets/subtensor/src/subnets/weights.rs`) requires
`current_epoch == commit_epoch + commit_reveal_period`. Revealing earlier
fails with `RevealTooEarly`; once the current epoch moves past that target,
`is_commit_expired` drops the commit and a late reveal fails with
`ExpiredWeightCommit`. A hotkey may hold at most 10 unrevealed commits.

The value is bounded on-chain: `set_reveal_period` accepts 1 to 100 epochs.

In practice validators rarely reveal by hand. `btcli tx set-weights` (the
`set_weights` intent) uses timelocked commits: it reads `RevealPeriodEpochs`
and the subnet's epoch schedule, computes the drand round whose randomness
becomes available in the reveal epoch, and encrypts the payload to that round
— the chain then decrypts and applies the weights itself, with no reveal
transaction.

<HyperparamWeightsRules focus="commit_reveal_period" />

## Reading and setting [#reading-and-setting]

```bash
btcli sudo get --netuid N --name commit_reveal_period
```

Owner-settable; the value is an epoch (tempo) count:

```bash
btcli sudo set --netuid N --name commit_reveal_period --value 2
```

## Related [#related]

* [`commit_reveal_weights_enabled`](/docs/hyperparameters/commit-reveal-weights-enabled) — the toggle that activates this delay
* [`tempo`](/docs/hyperparameters/tempo) — the block length of one epoch
* [`weights_rate_limit`](/docs/hyperparameters/weights-rate-limit) — cooldown applied at commit time
* [`weights_version`](/docs/hyperparameters/weights-version) — version gate checked when revealed weights land