feat: NFT with "transient" storage shield flow

[benesjan]

Adds an implementation of an NFT that allows minting and burning in public-only and transfers in both public and private. It also works as a demonstration of the transient storage shield flow. I decided to demonstrate the new shield flow on this NFT because it works the same way as for a token and I didn't feel like copying the old shield flows from a token.

[benesjan]

• feat: NFT with "transient" storage shield flow #8129 👈
• feat: tuple return value typescript decoding #8319
• master

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[sklppy88]

I like the central idea of having a public registry of sorts in nft_exists to be a part of the standard (maybe this is necessitated by the requirements, as I'm not even sure how a purely private one would look like). I feel like it lends to a good balance of transparency and privacy. Elegant, imo.

[benesjan]

@nventuro does the interface looks good enough to you now?

If yes I would probably go ahead and implement it (might tackle the token shield spec first).

[AztecBot]

Benchmark results

Metrics with a significant change:

• protocol_circuit_simulation_time_in_ms (private-kernel-tail-to-public): 1,371 (+74%)
• avm_simulation_time_ms (FeeJuice:_increase_public_balance): 135 (+214%)

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	5,757	1,552 (+1%)	706 (+1%)	743 (-3%)	774
proof_construction_time_sha256_30_ms	11,563	3,072	1,368 (-1%)	1,407 (-1%)	1,460
proof_construction_time_sha256_100_ms	45,686 (+1%)	11,848 (-2%)	5,409	5,397 (-1%)	5,396 (+1%)
proof_construction_time_poseidon_hash_ms	79.0	34.0	34.0	58.0	88.0
proof_construction_time_poseidon_hash_30_ms	1,534	441 (+6%)	200 (-1%)	224 (-1%)	271 (+1%)
proof_construction_time_poseidon_hash_100_ms	5,675	1,509	676	723	748 (+1%)

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	4,612	8,260	15,524
l1_rollup_calldata_gas	52,876	97,648	186,836
l1_rollup_execution_gas	819,562	1,555,742	3,346,365
l2_block_processing_time_in_ms	252 (-3%)	447 (+2%)	797 (-1%)
l2_block_building_time_in_ms	9,151 (-1%)	18,210	36,303
l2_block_rollup_simulation_time_in_ms	9,151 (-1%)	18,210	36,303
l2_block_public_tx_process_time_in_ms	7,781 (-1%)	16,811	34,881 (+1%)

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	3,145 (+6%)	4,005 (+1%)
node_database_size_in_bytes	14,225,648	18,231,536
pxe_database_size_in_bytes	16,258	26,818

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	input_size_in_bytes	output_size_in_bytes	proving_time_in_ms
private-kernel-init	74.2 (+6%)	377	20,971	44,933	N/A
private-kernel-inner	140 (+1%)	698 (+1%)	71,782	45,067	N/A
private-kernel-reset-tiny	317 (-2%)	693 (+1%)	64,268	44,922	N/A
private-kernel-tail	150	131 (+1%)	50,548	57,178	N/A
base-parity	6.03	N/A	160	96.0	N/A
root-parity	35.5 (-1%)	N/A	73,964	96.0	N/A
base-rollup	2,090 (+1%)	N/A	189,128	664	N/A
block-root-rollup	42.0 (-1%)	N/A	58,217	2,448	N/A
public-kernel-setup	85.6	N/A	114,433	79,670	N/A
public-kernel-app-logic	98.3	N/A	114,251	79,670	N/A
public-kernel-tail	573 (+1%)	N/A	487,098	16,414	N/A
private-kernel-reset-small	292	N/A	66,345	45,629	N/A
private-kernel-tail-to-public	⚠️ 1,371 (+74%)	604 (+1%)	447,477	1,825	N/A
public-kernel-teardown	84.6 (-1%)	N/A	114,697	79,670	N/A
merge-rollup	20.4	N/A	38,182	664	N/A
undefined	N/A	N/A	N/A	N/A	106,103 (+1%)

Stats on running time collected for app circuits

Function	input_size_in_bytes	output_size_in_bytes	witness_generation_time_in_ms
ContractClassRegisterer:register	1,344	11,731	344 (-1%)
ContractInstanceDeployer:deploy	1,408	11,731	19.1 (-1%)
MultiCallEntrypoint:entrypoint	1,920	11,731	423
FeeJuice:deploy	1,376	11,731	396 (+1%)
SchnorrAccount:constructor	1,312	11,731	63.3 (-2%)
SchnorrAccount:entrypoint	2,336	11,731	371 (-1%)
FeeJuice:claim	1,344	11,731	39.0 (+1%)
Token:privately_mint_private_note	1,280	11,731	74.9 (+5%)
FPC:fee_entrypoint_public	1,344	11,731	24.6
Token:transfer	1,312	11,731	208 (-1%)
Benchmarking:create_note	1,344	11,731	78.4 (+1%)
SchnorrAccount:verify_private_authwit	1,280	11,731	27.0 (-2%)
Token:unshield	1,376	11,731	532 (+6%)
FPC:fee_entrypoint_private	1,376	11,731	703 (-2%)

AVM Simulation

Time to simulate various public functions in the AVM.

Function	time_ms	bytecode_size_in_bytes
FeeJuice:_increase_public_balance	⚠️ 135 (+214%)	1,197
FeeJuice:set_portal	10.7 (+1%)	1,179
Token:constructor	282 (-1%)	10,585
FPC:constructor	74.2 (+1%)	7,987
FeeJuice:check_balance	37.1	1,004
Token:mint_public	45.3 (-10%)	2,122
Token:assert_minter_and_mint	258 (+5%)	1,434
AuthRegistry:set_authorized	46.0 (+24%)	501
FPC:prepare_fee	89.0 (+3%)	1,379
Token:transfer_public	19.2 (+15%)	8,730
FPC:pay_refund	39.2 (-3%)	1,915
Benchmarking:increment_balance	987	1,575
Token:_increase_public_balance	37.6 (-5%)	1,168
FPC:pay_refund_with_shielded_rebate	53.0 (+5%)	1,915

Public DB Access

Time to access various public DBs.

Function	time_ms
get-nullifier-index	0.168 (+2%)

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	2.14 (-1%)	3.85 (-1%)	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	0.112	0.108 (-1%)	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_32_depth_ms	N/A	N/A	11.0 (-1%)	17.4 (-1%)	30.5 (-2%)	59.6 (+1%)	113 (-1%)
batch_insert_into_append_only_tree_32_depth_hash_count	N/A	N/A	95.9	159	287	543	1,055
batch_insert_into_append_only_tree_32_depth_hash_ms	N/A	N/A	0.106 (-1%)	0.101 (-1%)	0.0988 (-2%)	0.102	0.101 (-1%)
batch_insert_into_indexed_tree_20_depth_ms	N/A	N/A	14.1 (-1%)	26.0	43.5 (-2%)	82.3	160 (-2%)
batch_insert_into_indexed_tree_20_depth_hash_count	N/A	N/A	109	207	357	691	1,363
batch_insert_into_indexed_tree_20_depth_hash_ms	N/A	N/A	0.108 (-1%)	0.105	0.104 (-2%)	0.102	0.100 (-1%)
batch_insert_into_indexed_tree_40_depth_ms	N/A	N/A	16.1	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_count	N/A	N/A	129	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_ms	N/A	N/A	0.106	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	72,419	668,302

Transaction size based on fee payment method

| Metric | |
| - | |

[nventuro]

Fantastic job 🙌