test: add test to showcase private token exploits

[LHerskind]

The PrivateToken that was introduced in #7226 have critical vulnerabilities:

1. It does not take into account key rotation, so if you rotate your keys your entire balance is lost.
2. It does not actually require the signing key to be used to be spend notes, meaning that if the PXE is compromised your funds are gone and it does not matter that your account contract is using a key only on a hardware wallet etc.

This pr showcase how to exploit the two weaknesses.

[LHerskind]

• test: add test to showcase private token exploits #7297 👈
• master

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[AztecBot]

Benchmark results

Metrics with a significant change:

• proof_construction_time_sha256_100_ms (16): 5,434 (-18%)
• proof_construction_time_sha256_30_ms (16): 1,411 (-20%)
• avm_simulation_time_ms (Token:mint_public): 491 (+1045%)
• avm_simulation_time_ms (Token:assert_minter_and_mint): 58.1 (-67%)

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	5,709	1,544	706	747 (-1%)	771 (-1%)
proof_construction_time_sha256_30_ms	11,715 (-2%)	3,131 (-2%)	⚠️ 1,411 (-20%)	1,426 (-11%)	1,463 (-7%)
proof_construction_time_sha256_100_ms	43,665 (-1%)	11,788 (-1%)	⚠️ 5,434 (-18%)	5,402 (-7%)	5,356 (-5%)
proof_construction_time_poseidon_hash_ms	78.0	34.0	34.0 (-23%)	58.0 (-11%)	87.0 (-4%)
proof_construction_time_poseidon_hash_30_ms	1,516	413 (-1%)	200 (-1%)	222 (-4%)	269 (+1%)
proof_construction_time_poseidon_hash_100_ms	5,730 (-2%)	1,562	720 (-1%)	794 (+2%)	787 (-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	1,412	1,412	1,412
l1_rollup_calldata_gas	9,476	9,468	9,476
l1_rollup_execution_gas	611,215	611,358	611,517
l2_block_processing_time_in_ms	760 (-2%)	1,424 (+1%)	2,692 (-1%)
l2_block_building_time_in_ms	20,812 (-1%)	41,813 (-1%)	81,579 (-1%)
l2_block_rollup_simulation_time_in_ms	20,812 (-1%)	41,812 (-1%)	81,579 (-1%)
l2_block_public_tx_process_time_in_ms	17,807 (-1%)	38,584	78,408 (-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	7,043	10,003 (+1%)
node_database_size_in_bytes	12,259,408	16,207,952
pxe_database_size_in_bytes	16,254	26,813

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	102	390 (+2%)	12,791 (+1%)	19,482	54,134	73,920	2,243	524,288
private-kernel-inner	308	769 (-2%)	52,186 (+6%)	80,694	54,134	73,920	2,243	2,097,152
private-kernel-tail	1,086	2,605 (+2%)	48,607	61,457	62,057	14,912	399	2,097,152
base-parity	6.15	1,550 (+2%)	2,720 (+4%)	128	64.0	2,208	2.00	131,072
root-parity	49.0 (+1%)	74.0 (+11%)	40,025 (-2%)	27,100	64.0	2,720	18.0	2,097,152
base-rollup	6,573	4,870	92,372 (+2%)	170,330	728	3,648	47.0	4,194,304
root-rollup	112 (+3%)	83.0 (+7%)	23,938 (-3%)	25,253	620	3,456	41.0	1,048,576
public-kernel-setup	545 (+1%)	2,444 (+3%)	43,606 (+2%)	102,121	80,278	106,912	3,274	2,097,152
public-kernel-app-logic	502	3,412 (+2%)	44,890 (+3%)	102,121	80,278	106,912	3,274	2,097,152
public-kernel-tail	1,147	26,959	184,627 (+4%)	399,014	10,014	14,912	399	8,388,608
private-kernel-reset-small	467	1,081 (+1%)	31,378 (+2%)	109,233	54,134	73,920	2,243	1,048,576
public-kernel-teardown	494 (+1%)	3,422 (+3%)	44,215 (+2%)	102,121	80,278	106,912	3,274	2,097,152
merge-rollup	29.2 (-1%)	N/A	N/A	16,486	728	N/A	N/A	N/A
private-kernel-tail-to-public	N/A	8,802 (+4%)	53,028 (+4%)	N/A	N/A	106,912	3,274	2,097,152

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	8,792	407 (+1%)	N/A	N/A	N/A	N/A
ContractInstanceDeployer:deploy	1,408	8,792	38.8 (+1%)	N/A	N/A	N/A	N/A
MultiCallEntrypoint:entrypoint	1,920	8,792	1,195 (+1%)	N/A	N/A	N/A	N/A
GasToken:deploy	1,376	8,792	910 (+2%)	N/A	N/A	N/A	N/A
SchnorrAccount:constructor	1,312	8,792	489 (+1%)	N/A	N/A	N/A	N/A
SchnorrAccount:entrypoint	2,304	8,792	1,628 (+1%)	14,720	54,020 (-1%)	2,097,152	393
Token:privately_mint_private_note	1,280	8,792	628 (+1%)	N/A	N/A	N/A	N/A
FPC:fee_entrypoint_public	1,344	8,792	268 (+1%)	14,720	11,870 (+3%)	524,288	393
Token:transfer	1,312	8,792	1,804 (+2%)	14,720	13,526 (+7%)	524,288	393
AuthRegistry:set_authorized (avm)	19,226	N/A	N/A	91,264	1,357 (+2%)	N/A	N/A
FPC:prepare_fee (avm)	26,668	N/A	N/A	91,328	3,059 (+3%)	N/A	N/A
Token:transfer_public (avm)	42,918	N/A	N/A	91,328	4,107 (+5%)	N/A	N/A
AuthRegistry:consume (avm)	33,104	N/A	N/A	91,264	3,017 (+5%)	N/A	N/A
FPC:pay_refund (avm)	36,833	N/A	N/A	91,296	23,577	N/A	N/A
Benchmarking:create_note	1,344	8,792	480	N/A	N/A	N/A	N/A
SchnorrAccount:verify_private_authwit	1,280	8,792	72.8 (+2%)	N/A	N/A	N/A	N/A
Token:unshield	1,376	8,792	1,541 (+1%)	N/A	N/A	N/A	N/A
FPC:fee_entrypoint_private	1,376	8,792	2,132 (+1%)	N/A	N/A	N/A	N/A

AVM Simulation

Time to simulate various public functions in the AVM.

Function	time_ms	bytecode_size_in_bytes
GasToken:_increase_public_balance	67.1 (-2%)	13,790
GasToken:set_portal	16.8 (-4%)	3,339
Token:constructor	92.8	23,692
FPC:constructor	64.4 (+3%)	13,592
GasToken:mint_public	52.0 (-1%)	10,158
Token:mint_public	⚠️ 491 (+1045%)	19,034
Token:assert_minter_and_mint	⚠️ 58.1 (-67%)	12,925
AuthRegistry:set_authorized	33.1	7,812
FPC:prepare_fee	108 (-6%)	15,062
Token:transfer_public	43.3 (-17%)	31,218
FPC:pay_refund	129 (-7%)	25,260
Benchmarking:increment_balance	2,196	15,267
Token:_increase_public_balance	56.2 (+1%)	15,006
FPC:pay_refund_with_shielded_rebate	120 (+3%)	26,347

Public DB Access

Time to access various public DBs.

Function	time_ms
get-nullifier-index	0.161 (+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	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	16.8	31.7	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_ms	0.598 (-1%)	0.517	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_32_depth_ms	N/A	N/A	48.3	75.7 (-1%)	136 (+3%)	245	470 (-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	0.494	0.465 (-1%)	0.468 (+3%)	0.444	0.439 (-1%)
batch_insert_into_indexed_tree_20_depth_ms	N/A	N/A	59.5 (-1%)	112	183 (-1%)	354	693 (-1%)
batch_insert_into_indexed_tree_20_depth_hash_count	N/A	N/A	109	207	355	691	1,363
batch_insert_into_indexed_tree_20_depth_hash_ms	N/A	N/A	0.502 (-1%)	0.501	0.484 (-1%)	0.479	0.476 (-1%)
batch_insert_into_indexed_tree_40_depth_ms	N/A	N/A	73.0	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_count	N/A	N/A	133	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_ms	N/A	N/A	0.519	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	74,057	667,850

Transaction size based on fee payment method

| Metric | |
| - | |

[just-mitch]

Beautiful illustrations @LHerskind ! I think we should merge this. I created #7324 and #7323 which should be able to get these tests to fail when they are working.

[LHerskind]

Closed as this was just done to showcase issues that could then be addressed separately. Those issues should be addressed by now in #7319.