Alpha Vault — Timelock Contract

An ink! smart contract deployed on Bittensor (Subtensor) that manages coldkey ownership of alpha (subnet stake) for a configurable lock period.

Alpha itself never moves. Only the coldkey owner changes via transfer_stake. The hotkey and staking position on the subnet remain unchanged throughout.

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When the Contract Is Used

The contract is invoked every time alpha ownership moves to a user — which happens in three scenarios:

Scenario	Alpha recipient
Fill a sell order (buyer fills)	Buyer receives alpha
Fill a buy order (seller fills)	Buyer receives alpha
Close a sell order (no fill)	Seller gets alpha back

In all cases, instead of transferring alpha ownership directly to the user, the backend first transfers it to the contract coldkey, records a lock, and the user claims ownership after the lock period expires.

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How It Works

1. Alpha ownership moves to the contract
   transfer_stake(escrow coldkey → contract coldkey, same hotkey, netuid)
   → contract now owns the alpha on that hotkey

2. Backend records the lock
   contract.lock(recipient_coldkey, hotkey, netuid, amount, lock_blocks)
   → records who receives ownership and when

3. After lock_blocks elapse, recipient claims ownership
   contract.release(deposit_id)
   → transfer_stake(contract coldkey → recipient coldkey, same hotkey, netuid)
   → recipient now owns the alpha; hotkey and subnet unchanged

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Messages

Message	Caller	Description
lock(recipient, hotkey, netuid, amount, lock_blocks)	Owner	Record a new lock after transfer_stake(escrow → contract)
release(deposit_id)	Recipient only	Transfer ownership to recipient after lock expires
emergency_release(deposit_id)	Owner only	Force ownership transfer before expiry; still goes to the recorded recipient
set_min_lock_blocks(blocks)	Owner only	Update minimum lock duration
transfer_ownership(new_owner)	Owner only	Hand contract ownership to a new account
is_locked(deposit_id)	Anyone	Returns true if lock is still active
blocks_remaining(deposit_id)	Anyone	Blocks until lock expires (0 if expired)
get_lock(deposit_id)	Anyone	Full lock record

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Chain Extension

Uses the Subtensor chain extension (extension 0, function 6 — transfer_stake).
Reference: Subtensor WASM Contracts

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Build

Requires cargo-contract and ink! < 6.0.

cargo contract build

Artifacts are output to target/ink/.

Test

cargo test

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Notes

• amount is in rao units (1 alpha = 1_000_000_000 rao).
• The contract owner is the account that deploys the contract (the backend operator).
• emergency_release cannot redirect alpha — it always goes to the recipient recorded at lock time.
• One contract handles all trades; each trade gets a unique deposit_id.