feat(AggLayer): `B2AGG` note consumption check #2334

mmagician · 2026-01-23T14:08:03Z

As per the discussion here, the network target account ID is placed into NoteAttachment instead.

While at it, I created a helper function, similarly to the one we have for CLAIM notes: create_b2agg_note, and refactored the tests to use that utility.

TODO:

apply the same check to UPDATE_GER note (once feat(AggLayer): UPDATE_GER note #2333 lands)
what NoteAttachmentScheme should be used?

closes #2173
closes #2189

crates/miden-agglayer/asm/note_scripts/B2AGG.masm

crates/miden-agglayer/src/bridge_out.rs

- make bridge a network account - move the ID check to non-reclaim branch

crates/miden-agglayer/asm/note_scripts/B2AGG.masm

bobbinth

Looks good! Thank you! I left some comments inline. Also, I think it may make sense to merge this PR after #2338.

bobbinth · 2026-01-25T21:49:00Z

crates/miden-agglayer/asm/note_scripts/B2AGG.masm

+const ERR_B2AGG_TARGET_ACCOUNT_MISMATCH="B2AGG note attachment target account does not match consuming account"
+

 #! Bridge-to-AggLayer (B2AGG) note script: bridges assets from Miden to an AggLayer-connected chain.


nit: let's add NOTE SCRIPT section header above this line.

bobbinth · 2026-01-25T21:50:03Z

crates/miden-agglayer/asm/note_scripts/B2AGG.masm

 #! - If the consuming account is the sender (reclaim): the note's assets are added back to the consuming account.
 #! - If the consuming account is the Agglayer Bridge: the note's assets are moved to a BURN note, 
 #!   and the note details are hashed into a leaf and appended to the Local Exit Tree.
 #!   global exit root (GER) merkle tree structure.


This statement seems to be dangling (and not sure if it is relevant here).

bobbinth · 2026-01-25T21:53:03Z

crates/miden-agglayer/asm/note_scripts/B2AGG.masm

+        # Ensure note attachment targets the consuming bridge account.
+        exec.active_note::get_metadata
+        # => [NOTE_ATTACHMENT, METADATA_HEADER, pad(8)]
+
+        # TODO simplify once https://github.com/0xMiden/miden-base/pull/2338 lands
+
+        swapw dropw
+        # => [NOTE_ATTACHMENT, pad(12)]
+
+        # Reorder attachment word to [target_id_prefix, target_id_suffix].
+        drop drop
+        # => [target_id_prefix, target_id_suffix, pad(14)] (auto-padding)


nit: I would move this into a helper procedure. This way, once #2338 land, we can just replace the procedure name here. Although, it may make sense to merge this one after #2338 lands (or based this PR on #2338).

bobbinth · 2026-01-25T21:56:08Z

crates/miden-agglayer/asm/note_scripts/UPDATE_GER.masm

 const ERR_UPDATE_GER_UNEXPECTED_NUMBER_OF_STORAGE_ITEMS = "UPDATE_GER script expects exactly 8 note storage items"
+const ERR_UPDATE_GER_TARGET_ACCOUNT_MISMATCH = "UPDATE_GER note attachment target account does not match consuming account"

 #! Agglayer Bridge UPDATE_GER script: updates the GER by calling the bridge_in::update_ger function.


nit: let's add NOTE SCRIPT section header above this line.

bobbinth · 2026-01-25T22:01:30Z

crates/miden-agglayer/src/bridge_out.rs

+/// Contains the destination network and address information required
+/// for bridging assets to the AggLayer network.
+#[derive(Debug, Clone)]


nit: comment wrapping.

bobbinth · 2026-01-25T22:02:23Z

crates/miden-agglayer/src/bridge_out.rs

+    /// Destination network identifier (AggLayer-assigned network ID)
+    pub destination_network: u32,
+    /// Destination Ethereum address (20 bytes)
+    pub destination_address: EthAddressFormat,


nit (and not related to this PR): I think we should call it just EthAddress rather than EthAddressFormat.

It used to be call EthAddress, but was renamed as per #2238 (comment)

However, this was in the light of bridging-in, where we were passing a 160 bit value that was represented as an address on Ethereum, but was in fact encoding a Miden AccountId - i.e. it was not a "valid" Ethereum address ("valid" in the sense that there was no account associated with it).

In the bridging out flow, the value carried by the B2AGG note will actually be a valid Ethereum destination address.

I wouldn't change the naming to EthAddress (because it is not strictly correct) across the board.
I think the best solution here is to:

create a separate EthAddress dedicated for the bridging-out flow. It also wouldn't have methods such as from_account_id(account_id: AccountId) as they don't make sense there.

keep EthAddress as the base struct, and create a EthAddressFormat trait to encompass Miden<>Ethereum conversion logic like from_account_id / from_account_id

WDYT?

bobbinth · 2026-01-25T22:05:24Z

crates/miden-agglayer/src/bridge_out.rs

+/// # Parameters
+/// - `storage`: The destination network and address information
+/// - `assets`: The assets to bridge (must be fungible assets from a network faucet)
+/// - `target_account_id`: The account ID that will consume this note (bridge account)
+/// - `sender_account_id`: The account ID of the note creator
+/// - `note_type`: The type of note (Public or Private)
+/// - `rng`: Random number generator for creating the note serial number


Do we need note_type here? I think B2AGG notes would have to always be public (otherwise, the bridge can't process them).

bobbinth · 2026-01-25T22:06:26Z

crates/miden-agglayer/src/bridge_out.rs

+    let tag = NoteTag::new(0);
+
+    let attachment = NoteAttachment::from(
+        NetworkAccountTarget::new(target_account_id, NoteExecutionHint::None)


I think we should use NoteExecutionHint::Always here because B2AGG notes are always consumable.

bobbinth · 2026-01-25T22:08:55Z

crates/miden-agglayer/src/lib.rs


-    let bridge_out_component = bridge_out_component(vec![]);
+    // Create the "bridge_out" component
+    let let_storage_slot_name = StorageSlotName::new("miden::agglayer::let").unwrap();


Maybe not for this PR, but we should normalize storage slot naming. For example, this should be miden::agglayer::bridge::let to be consistent with miden::agglayer::bridge::ger_upper and miden::agglayer::bridge::ger_lower (which I think should be just one slot miden::agglayer::bridge::ger).

PhilippGackstatter

Looks good to me (only reviewed the note attachment parts - let me know if you want me to review everything).

PhilippGackstatter · 2026-01-26T10:24:22Z

crates/miden-agglayer/src/bridge_out.rs

+///
+/// # Errors
+/// Returns an error if note creation fails.
+pub fn create_b2agg_note<R: FeltRng>(


FYI: For future note creation functions, I think we should directly implement the approach described in #2283, since we'll have to migrate all standard note types to this approach anyway.

PhilippGackstatter · 2026-01-26T10:26:25Z

crates/miden-agglayer/src/bridge_out.rs

+    let b2agg_script = b2agg_script();
+    let recipient = NoteRecipient::new(
+        rng.draw_word(),
+        miden_protocol::note::NoteScript::new(b2agg_script),


Suggested change

miden_protocol::note::NoteScript::new(b2agg_script),

NoteScript::new(b2agg_script),

Nit

mmagician requested a review from partylikeits1983 January 23, 2026 14:19

mmagician added the agglayer label Jan 23, 2026

PhilippGackstatter reviewed Jan 23, 2026

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crates/miden-agglayer/src/bridge_out.rs Outdated Show resolved Hide resolved

mmagician added 5 commits January 24, 2026 11:07

feat: put target account in attachment

181b25d

feat: extract b2agg creation to helper

a89766f

lint: regen error file

841f839

feat: use NetworkAccountTarget for attachments

5b855fc

- make bridge a network account - move the ID check to non-reclaim branch

fix: still need LET slot

bec68d1

mmagician force-pushed the mmagician-bagg-check branch from 69ed247 to bec68d1 Compare January 24, 2026 11:08

mmagician added 2 commits January 24, 2026 11:14

chore: test the target mismatch logic

b00c976

chore: apply target checks to UPDATE_GER

2aba29c

mmagician commented Jan 24, 2026

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mmagician mentioned this pull request Jan 24, 2026

Create network target account helpers #2337

Open

mmagician added 2 commits January 24, 2026 15:00

chore: add TODOs

4b2f3fa

chore: lint

e3a4af1

mmagician marked this pull request as ready for review January 24, 2026 15:03

mmagician requested a review from PhilippGackstatter January 24, 2026 15:03

bobbinth reviewed Jan 25, 2026

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PhilippGackstatter approved these changes Jan 26, 2026

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		const ERR_B2AGG_TARGET_ACCOUNT_MISMATCH="B2AGG note attachment target account does not match consuming account"


		#! Bridge-to-AggLayer (B2AGG) note script: bridges assets from Miden to an AggLayer-connected chain.

	miden_protocol::note::NoteScript::new(b2agg_script),
	NoteScript::new(b2agg_script),

feat(AggLayer): B2AGG note consumption check #2334

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feat(AggLayer): `B2AGG` note consumption check #2334

feat(AggLayer): `B2AGG` note consumption check #2334

mmagician commented Jan 23, 2026 •

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