refactor: note emission

[LHerskind]

Adds a NoteEmission struct that is returned when new notes are created. The struct is the note and a NoteHashCount that can be used when emitting the note to ensure that squashing is possible.

There are fairly large change to return this struct throughout, and at the same time getting rid of the broadcast that we have currently been using whenever the create_note life cycle have been encountered. This also means that keys are not fed into the lifecycle! Meaning that the aztec nr libraries are generally getting less contaminated with log decisions.

Instead of always forcing an emit, the returned value can now be emitted using the emit which can be provided a function. For ease of use, we have also added encrypted_note_emission.nr which have a encode_and_encrypt and encode_and_encrypt_with_keys functions.

These functions can be used along with the emit to encrypt the note and then emit it. This allows us to execute it as:

    let amount = U128::from_integer(amount);
    storage.balances.sub(from, amount).emit(encode_and_encrypt(&mut context, from, from));
    storage.balances.add(to, amount).emit(encode_and_encrypt(&mut context, from, to));

TODO:

• Remove broadcast from note interface
• Remove encrypt_and_emit_note from private context

---

There are some build issues that need to be ironed out, but I think that the flow is nicer than before as it is more clear when things are emitted, and for cases where we are doing a get_note and then replace it is easier for us to not emit the read but only the update afterwards.

[LHerskind]

• feat: auth registry #7035
• test: add transfer to undeployed account #7015
• refactor: transfer and transferfrom to save constrains for simpler cases #7013
• refactor: note emission #7003 👈
• refactor: split log emission to encrypt and a log, remove address input #6987
• master

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[AztecBot]

Benchmark results

Metrics with a significant change:

• app_circuit_witness_generation_time_in_ms (FPC:fee_entrypoint_public): 382 (-64%)
• avm_simulation_time_ms (Token:mint_public): 546 (+732%)
• avm_simulation_time_ms (Token:assert_minter_and_mint): 56.7 (-74%)
• avm_simulation_time_ms (Token:_increase_public_balance): 142 (+146%)
• protocol_circuit_witness_generation_time_in_ms (private-kernel-inner): 962 (-17%)

Detailed results

All benchmarks are run on txs on the Benchmarking contract on the repository. Each tx consists of a batch call to create_note and increment_balance, which guarantees that each tx has a private call, a nested private call, a public call, and a nested public call, as well as an emitted private note, an unencrypted log, and public storage read and write.

This benchmark source data is available in JSON format on S3 here.

Proof generation

Each column represents the number of threads used in proof generation.

Metric	1 threads	4 threads	16 threads	32 threads	64 threads
proof_construction_time_sha256_ms	5,806 (+1%)	1,570 (+1%)	700	775 (-1%)	778
proof_construction_time_sha256_30_ms	11,674 (+1%)	3,108 (+1%)	1,388 (+1%)	1,437 (+1%)	1,474 (+1%)
proof_construction_time_sha256_100_ms	44,477 (+1%)	11,951	5,587 (+2%)	5,476	5,407 (+1%)
proof_construction_time_poseidon_hash_ms	79.0 (+1%)	34.0	34.0	57.0 (-2%)	88.0
proof_construction_time_poseidon_hash_30_ms	1,541 (+1%)	420	200	227 (+3%)	275 (+2%)
proof_construction_time_poseidon_hash_100_ms	5,817 (+1%)	1,590 (+1%)	730 (+1%)	786	802

L2 block published to L1

Each column represents the number of txs on an L2 block published to L1.

Metric	4 txs	8 txs	16 txs
l1_rollup_calldata_size_in_bytes	1,412	1,412	1,412
l1_rollup_calldata_gas	9,464	9,454	9,464
l1_rollup_execution_gas	610,285	610,275	610,285
l2_block_processing_time_in_ms	755	1,423 (+1%)	2,709 (+1%)
l2_block_building_time_in_ms	23,230 (+1%)	48,056 (+5%)	91,403 (+2%)
l2_block_rollup_simulation_time_in_ms	23,120 (+1%)	47,677 (+5%)	90,998 (+2%)
l2_block_public_tx_process_time_in_ms	19,834 (+1%)	44,045 (+5%)	87,537 (+2%)

L2 chain processing

Each column represents the number of blocks on the L2 chain where each block has 8 txs.

Metric	3 blocks	5 blocks
node_history_sync_time_in_ms	6,538 (+2%)	9,394 (+2%)
node_database_size_in_bytes	10,563,664	14,372,944
pxe_database_size_in_bytes	9,242	15,127

Circuits stats

Stats on running time and I/O sizes collected for every kernel circuit run across all benchmarks.

Circuit	simulation_time_in_ms	witness_generation_time_in_ms	proving_time_in_ms	input_size_in_bytes	output_size_in_bytes	proof_size_in_bytes	num_public_inputs	size_in_gates
private-kernel-init	136 (+5%)	483 (+1%)	13,244	20,634	65,142	90,304	2,755	524,288
private-kernel-inner	393 (+2%)	⚠️ 962 (-17%)	50,185 (-1%)	92,854	65,142	90,304	2,755	2,097,152
private-kernel-tail	377 (+2%)	1,847	54,161 (-2%)	97,073	73,629	14,912	399	2,097,152
base-parity	8.17 (+29%)	1,768 (-2%)	2,726 (-4%)	128	64.0	2,208	2.00	131,072
root-parity	49.7 (-2%)	61.2 (-3%)	40,970 (-2%)	27,100	64.0	2,720	18.0	2,097,152
base-rollup	7,962 (+4%)	4,369 (-4%)	85,029 (-3%)	170,330	756	3,648	47.0	4,194,304
root-rollup	110	74.2 (-6%)	23,285 (-6%)	25,309	620	3,456	41.0	1,048,576
public-kernel-setup	706	2,977	46,102 (+1%)	113,321	91,286	123,296	3,786	2,097,152
public-kernel-app-logic	596 (+1%)	3,875 (-3%)	44,895 (-8%)	113,321	91,286	123,296	3,786	2,097,152
public-kernel-tail	1,180 (+1%)	34,156 (-3%)	186,341 (-2%)	412,582	10,014	14,912	399	8,388,608
private-kernel-reset-small	596 (+1%)	1,970 (+1%)	47,082	121,265	65,142	90,304	2,755	2,097,152
public-kernel-teardown	602 (+1%)	3,959	46,963	113,321	91,286	123,296	3,786	2,097,152
merge-rollup	29.0 (-1%)	N/A	N/A	16,542	756	N/A	N/A	N/A
private-kernel-tail-to-public	N/A	7,106 (+3%)	99,370 (-2%)	N/A	N/A	123,296	3,786	4,194,304

Stats on running time collected for app circuits

Function	input_size_in_bytes	output_size_in_bytes	witness_generation_time_in_ms	proof_size_in_bytes	proving_time_in_ms	size_in_gates	num_public_inputs
ContractClassRegisterer:register	1,344	9,944	467 (+15%)	N/A	N/A	N/A	N/A
ContractInstanceDeployer:deploy	1,408	9,944	40.5	N/A	N/A	N/A	N/A
MultiCallEntrypoint:entrypoint	1,920	9,944	2,004 (+2%)	N/A	N/A	N/A	N/A
GasToken:deploy	1,376	9,944	1,012 (+5%)	N/A	N/A	N/A	N/A
SchnorrAccount:constructor	1,312	9,944	1,432	N/A	N/A	N/A	N/A
SchnorrAccount:entrypoint	2,304	9,944	2,818 (-1%)	16,768	54,331 (-4%)	2,097,152	457
Token:privately_mint_private_note	1,280	9,944	1,668	N/A	N/A	N/A	N/A
FPC:fee_entrypoint_public	1,344	9,944	⚠️ 382 (-64%)	16,768	10,943	524,288	457
Token:transfer	1,376	9,944	4,971 (-7%)	16,768	52,752	2,097,152	457
Benchmarking:create_note	1,344	9,944	1,394	N/A	N/A	N/A	N/A
SchnorrAccount:spend_private_authwit	1,280	9,944	83.7 (+10%)	N/A	N/A	N/A	N/A
Token:unshield	1,376	9,944	4,009 (+3%)	N/A	N/A	N/A	N/A
FPC:fee_entrypoint_private	1,376	9,944	4,983 (+3%)	N/A	N/A	N/A	N/A

AVM Simulation

Time to simulate various public functions in the AVM.

Function	time_ms
GasToken:_increase_public_balance	69.7 (-4%)
GasToken:set_portal	17.2
Token:constructor	96.3
FPC:constructor	61.0 (-11%)
GasToken:mint_public	52.6 (-2%)
Token:mint_public	⚠️ 546 (+732%)
Token:assert_minter_and_mint	⚠️ 56.7 (-74%)
SchnorrAccount:approve_public_authwit	33.5 (+2%)
FPC:prepare_fee	77.0 (+6%)
Token:transfer_public	45.7 (+6%)
FPC:pay_refund	70.4 (+7%)
Benchmarking:increment_balance	2,524 (+5%)
Token:_increase_public_balance	⚠️ 142 (+146%)
FPC:pay_refund_with_shielded_rebate	56.3 (+5%)

Public DB Access

Time to access various public DBs.

Function	time_ms
get-nullifier-index	0.180 (-3%)

Tree insertion stats

The duration to insert a fixed batch of leaves into each tree type.

Metric	1 leaves	16 leaves	64 leaves	128 leaves	256 leaves	512 leaves	1024 leaves
batch_insert_into_append_only_tree_16_depth_ms	10.3 (+1%)	16.8	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_count	16.7	31.8	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_ms	0.602 (+1%)	0.516 (+1%)	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_32_depth_ms	N/A	N/A	48.5	75.9 (+1%)	132 (+1%)	247 (+1%)	473 (+1%)
batch_insert_into_append_only_tree_32_depth_hash_count	N/A	N/A	95.9	159	288	543	1,055
batch_insert_into_append_only_tree_32_depth_hash_ms	N/A	N/A	0.495	0.468 (+1%)	0.454 (+1%)	0.447 (+1%)	0.442 (+1%)
batch_insert_into_indexed_tree_20_depth_ms	N/A	N/A	59.8 (+1%)	113 (+2%)	184 (+1%)	355 (+1%)	698 (+1%)
batch_insert_into_indexed_tree_20_depth_hash_count	N/A	N/A	109	208	355	691	1,363
batch_insert_into_indexed_tree_20_depth_hash_ms	N/A	N/A	0.506 (+1%)	0.505 (+1%)	0.483	0.481 (+1%)	0.479 (+1%)
batch_insert_into_indexed_tree_40_depth_ms	N/A	N/A	75.0 (+1%)	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_count	N/A	N/A	135	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_ms	N/A	N/A	0.523 (+1%)	N/A	N/A	N/A	N/A

Miscellaneous

Transaction sizes based on how many contract classes are registered in the tx.

Metric	0 registered classes	1 registered classes
tx_size_in_bytes	83,854	676,749

Transaction size based on fee payment method

| Metric | |
| - | |

[AztecBot]

Docs Preview

Hey there! 👋 You can check your preview at https://666996c850c0d7207daafc11--aztec-docs-dev.netlify.app

[benesjan]

Super nice! Love the explicit emit(...) and discard(...) calls.

Added just some nits.

[benesjan]

Suggested change

	To emit encrypted logs you can import the `encode_and_encrypt` or `encode_and_encrypt_with_keys` functions and pass them into the `emit` function after inserting a note. An example is seen in the token example contract transfer function:
	To emit encrypted logs you can import the `encode_and_encrypt` or `encode_and_encrypt_with_keys` functions and pass them into the `emit` function after inserting a note. An example can be seen in the reference token contract's transfer function:

[benesjan]

Super nice!

[benesjan]

Suggested change

	* A note emission struct containing the information required when to emit a note.
	* A note emission struct containing the information required for emitting a note.

[benesjan]

Suggested change

	note_emission::{NoteEmission, OuterNoteEmission}
	note_emission::NoteEmission

This import is unused.

[benesjan]

Suggested change

	* A wrapper of the note emission
	* A struct wrapping note emission in `Option<T>`.

Makes it a bit clearer.

[benesjan]

Suggested change

use crate::encrypted_logs::encrypted_note_emission::encode_and_encrypt_with_keys;

Unused import.

[benesjan]

🤤🤤🤤

[benesjan]

Suggested change

// The test note is not being broadcasted (TestNote::broadcast(...) does not actually broadcast) and for this

Stale comment here. Can be nuked now.

[benesjan]

Suggested change

// reason we are passing zero values for the public keys below. This means that if we want to interact with

[benesjan]

Suggested change

// this note in the future, we will need to manually add it to PXE by calling pxe.addNote(...).