feat: cumulative confirmations tier per BTC block#48
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olga24912
commented
Jun 22, 2026
| pub fn set_confirmations_strategy(&mut self, range_upper_bound: U128, confirmations: u8) { | ||
| assert_one_yocto(); | ||
| require!( | ||
| (2..=10).contains(&confirmations), |
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We should not have such limitations for ZCash
| // `verify_deposit_callback` takes 8 args (extra `confirmations_delta`); the `#[near]` | ||
| // proc-macro re-emits the signature in the ext-trait so the `clippy::too_many_arguments` | ||
| // lint fires from inside the macro expansion and an inner `#[allow]` doesn't reach it. | ||
| #![allow(clippy::too_many_arguments)] |
| pub tx_id: H256, | ||
| pub tx_block_blockhash: H256, | ||
| pub tx_index: u64, | ||
| pub merkle_proof: Vec<H256>, |
| &self, | ||
| #[serializer(borsh)] args: TxInclusionProof, | ||
| ) -> Option<TxInclusionInfo>; | ||
| fn verify_transaction_inclusion_with_heights_v2( |
| /// required-confirmations value, so a tx near the top tier still has room left | ||
| /// to be tracked across in-flight verifies. Chosen heuristically; not tied to | ||
| /// any protocol parameter. | ||
| pub const BLOCK_AMOUNT_RING_CAPACITY_SLACK: usize = 5; |
| pub fn max_tier_confirmations(&self) -> u8 { | ||
| self.confirmations_strategy | ||
| .values() | ||
| .copied() |
| refund_requests, | ||
| #[cfg(feature = "zcash")] | ||
| refund_requests: IterableMap::new(StorageKey::RefundRequests), | ||
| block_bridge_amounts: BlockAmountRing::new(ring_capacity), |
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Do we need to add extra Contract version for update?
| // SUM of bridge txs in a block, blocking an attacker from splitting one big deposit | ||
| // into many small ones to bypass the high-tier confirmations requirement. | ||
| // Capacity is derived from config; see `BlockAmountRing::capacity_for`. | ||
| pub block_bridge_amounts: BlockAmountRing, |
| #[cfg(feature = "zcash")] | ||
| refund_requests: IterableMap::new(StorageKey::RefundRequests), | ||
| block_bridge_amounts: BlockAmountRing::new(ring_capacity), | ||
| } |
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Add migration tests for the last contract versions
| // Refund-request is rare and already gated by `refund_timelock_sec`, so we | ||
| // skip the cumulative-amount ring entirely and just demand max-tier depth | ||
| // (see `Config::max_required_confirmations`). The callback doesn't need to | ||
| // know about the deposit amount or whitelist deltas. |
olga24912
commented
Jun 24, 2026
| let ext = ext_btc_light_client::ext(btc_light_client_account_id) | ||
| .with_static_gas(GAS_FOR_VERIFY_TRANSACTION_INCLUSION); | ||
| if let Some((coinbase_tx_id, coinbase_merkle_proof)) = coinbase_proof { | ||
| ext.verify_transaction_inclusion_with_heights_v2(TxInclusionProofV2::new( |
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Confirmations tier now computed against the SUM of bridge tx amounts in a BTC
block, closing the split-deposit bypass (one big deposit chunked into many
small to fall under a lower tier).
Per-block sums in a fixed-capacity ring keyed by
block_height % cap. Usesverify_transaction_inclusion_with_heights(Near-One/btc-light-client-contract#140) to get tip + block height in one call; confirmations check moves to our callback.