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refactor: minor tagging API improvement #13092

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Merged
benesjan merged 1 commit into from
Mar 31, 2025
Merged

refactor: minor tagging API improvement #13092

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76 changes: 22 additions & 54 deletions yarn-project/pxe/src/pxe_oracle_interface/pxe_oracle_interface.test.ts
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Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
import { PUBLIC_LOG_DATA_SIZE_IN_FIELDS } from '@aztec/constants';
import { timesParallel } from '@aztec/foundation/collection';
import { poseidon2Hash } from '@aztec/foundation/crypto';
import { Fq, Fr } from '@aztec/foundation/fields';
import type { Tuple } from '@aztec/foundation/serialize';
import { KeyStore } from '@aztec/key-store';
Expand All @@ -11,7 +10,7 @@ import { AztecAddress } from '@aztec/stdlib/aztec-address';
import { randomInBlock } from '@aztec/stdlib/block';
import { CompleteAddress } from '@aztec/stdlib/contract';
import type { AztecNode } from '@aztec/stdlib/interfaces/client';
import { computeAddress, computeTaggingSecretPoint, deriveKeys } from '@aztec/stdlib/keys';
import { computeAddress, computeAppTaggingSecret, deriveKeys } from '@aztec/stdlib/keys';
import { IndexedTaggingSecret, PrivateLog, PublicLog, TxScopedL2Log } from '@aztec/stdlib/logs';
import { randomContractArtifact, randomContractInstanceWithAddress } from '@aztec/stdlib/testing';
import { TxEffect, TxHash } from '@aztec/stdlib/tx';
Expand All @@ -37,10 +36,9 @@ async function computeSiloedTagForIndex(
contractAddress: AztecAddress,
index: number,
) {
const secretPoint = await computeTaggingSecretPoint(sender.completeAddress, sender.ivsk, recipient);
const appSecret = await poseidon2Hash([secretPoint.x, secretPoint.y, contractAddress]);
const tag = await poseidon2Hash([appSecret, recipient, index]);
return poseidon2Hash([contractAddress, tag]);
const appSecret = await computeAppTaggingSecret(sender.completeAddress, sender.ivsk, recipient, contractAddress);
const indexedTaggingSecret = new IndexedTaggingSecret(appSecret, index);
return indexedTaggingSecret.computeSiloedTag(recipient, contractAddress);
}

describe('PXEOracleInterface', () => {
Expand Down Expand Up @@ -175,14 +173,9 @@ describe('PXEOracleInterface', () => {

const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
const secrets = await Promise.all(
senders.map(async sender => {
const firstSenderSecretPoint = await computeTaggingSecretPoint(
recipient,
ivsk,
sender.completeAddress.address,
);
return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
}),
senders.map(sender =>
computeAppTaggingSecret(recipient, ivsk, sender.completeAddress.address, contractAddress),
),
);

// First sender should have 2 logs, but keep index 1 since they were built using the same tag
Expand Down Expand Up @@ -210,14 +203,9 @@ describe('PXEOracleInterface', () => {
// Recompute the secrets (as recipient) to ensure indexes are updated
const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
const secrets = await Promise.all(
senders.map(async sender => {
const firstSenderSecretPoint = await computeTaggingSecretPoint(
recipient,
ivsk,
sender.completeAddress.address,
);
return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
}),
senders.map(sender =>
computeAppTaggingSecret(recipient, ivsk, sender.completeAddress.address, contractAddress),
),
);

const indexesAsSender = await taggingDataProvider.getTaggingSecretsIndexesAsSender(secrets);
Expand Down Expand Up @@ -268,14 +256,9 @@ describe('PXEOracleInterface', () => {
// Recompute the secrets (as recipient) to ensure indexes are updated
const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
const secrets = await Promise.all(
senders.map(async sender => {
const firstSenderSecretPoint = await computeTaggingSecretPoint(
recipient,
ivsk,
sender.completeAddress.address,
);
return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
}),
senders.map(sender =>
computeAppTaggingSecret(recipient, ivsk, sender.completeAddress.address, contractAddress),
),
);

// First sender should have 2 logs, but keep index 1 since they were built using the same tag
Expand All @@ -298,14 +281,9 @@ describe('PXEOracleInterface', () => {
// Recompute the secrets (as recipient) to update indexes
const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
const secrets = await Promise.all(
senders.map(async sender => {
const firstSenderSecretPoint = await computeTaggingSecretPoint(
recipient,
ivsk,
sender.completeAddress.address,
);
return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
}),
senders.map(sender =>
computeAppTaggingSecret(recipient, ivsk, sender.completeAddress.address, contractAddress),
),
);

// Increase our indexes to 2
Expand Down Expand Up @@ -339,14 +317,9 @@ describe('PXEOracleInterface', () => {
// Recompute the secrets (as recipient) to update indexes
const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
const secrets = await Promise.all(
senders.map(async sender => {
const firstSenderSecretPoint = await computeTaggingSecretPoint(
recipient,
ivsk,
sender.completeAddress.address,
);
return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
}),
senders.map(sender =>
computeAppTaggingSecret(recipient, ivsk, sender.completeAddress.address, contractAddress),
),
);

// We set the indexes to WINDOW_HALF_SIZE + 1 so that it's outside the window and for this reason no updates
Expand Down Expand Up @@ -377,14 +350,9 @@ describe('PXEOracleInterface', () => {
// Recompute the secrets (as recipient) to update indexes
const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
const secrets = await Promise.all(
senders.map(async sender => {
const firstSenderSecretPoint = await computeTaggingSecretPoint(
recipient,
ivsk,
sender.completeAddress.address,
);
return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
}),
senders.map(sender =>
computeAppTaggingSecret(recipient, ivsk, sender.completeAddress.address, contractAddress),
),
);

await taggingDataProvider.setTaggingSecretsIndexesAsRecipient(
Expand Down
16 changes: 6 additions & 10 deletions yarn-project/pxe/src/pxe_oracle_interface/pxe_oracle_interface.ts
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
import { type L1_TO_L2_MSG_TREE_HEIGHT, MAX_NOTE_HASHES_PER_TX, PRIVATE_LOG_SIZE_IN_FIELDS } from '@aztec/constants';
import { timesParallel } from '@aztec/foundation/collection';
import { poseidon2Hash, randomInt } from '@aztec/foundation/crypto';
import { randomInt } from '@aztec/foundation/crypto';
import { Fr, Point } from '@aztec/foundation/fields';
import { createLogger } from '@aztec/foundation/log';
import type { KeyStore } from '@aztec/key-store';
Expand All @@ -26,7 +26,7 @@ import type { CompleteAddress, ContractInstance } from '@aztec/stdlib/contract';
import { computeUniqueNoteHash, siloNoteHash, siloNullifier } from '@aztec/stdlib/hash';
import type { AztecNode } from '@aztec/stdlib/interfaces/client';
import type { KeyValidationRequest } from '@aztec/stdlib/kernel';
import { computeAddressSecret, computeTaggingSecretPoint } from '@aztec/stdlib/keys';
import { computeAddressSecret, computeAppTaggingSecret } from '@aztec/stdlib/keys';
import {
IndexedTaggingSecret,
LogWithTxData,
Expand Down Expand Up @@ -333,10 +333,7 @@ export class PXEOracleInterface implements ExecutionDataProvider {
async #calculateAppTaggingSecret(contractAddress: AztecAddress, sender: AztecAddress, recipient: AztecAddress) {
const senderCompleteAddress = await this.getCompleteAddress(sender);
const senderIvsk = await this.keyStore.getMasterIncomingViewingSecretKey(sender);
const secretPoint = await computeTaggingSecretPoint(senderCompleteAddress, senderIvsk, recipient);
// Silo the secret so it can't be used to track other app's notes
const appSecret = poseidon2Hash([secretPoint.x, secretPoint.y, contractAddress]);
return appSecret;
return computeAppTaggingSecret(senderCompleteAddress, senderIvsk, recipient, contractAddress);
}

/**
Expand All @@ -362,10 +359,9 @@ export class PXEOracleInterface implements ExecutionDataProvider {
...(await this.keyStore.getAccounts()),
].filter((address, index, self) => index === self.findIndex(otherAddress => otherAddress.equals(address)));
const appTaggingSecrets = await Promise.all(
senders.map(async contact => {
const sharedSecret = await computeTaggingSecretPoint(recipientCompleteAddress, recipientIvsk, contact);
return poseidon2Hash([sharedSecret.x, sharedSecret.y, contractAddress]);
}),
senders.map(contact =>
computeAppTaggingSecret(recipientCompleteAddress, recipientIvsk, contact, contractAddress),
),
);
const indexes = await this.taggingDataProvider.getTaggingSecretsIndexesAsRecipient(appTaggingSecrets);
return appTaggingSecrets.map((secret, i) => new IndexedTaggingSecret(secret, indexes[i]));
Expand Down
18 changes: 12 additions & 6 deletions yarn-project/stdlib/src/keys/derivation.ts
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
import { GeneratorIndex } from '@aztec/constants';
import { Grumpkin, poseidon2HashWithSeparator, sha512ToGrumpkinScalar } from '@aztec/foundation/crypto';
import { Grumpkin, poseidon2Hash, poseidon2HashWithSeparator, sha512ToGrumpkinScalar } from '@aztec/foundation/crypto';
import { Fq, Fr, GrumpkinScalar } from '@aztec/foundation/fields';

import { AztecAddress } from '../aztec-address/index.js';
Expand Down Expand Up @@ -123,11 +123,7 @@ export async function deriveKeys(secretKey: Fr) {
}

// Returns shared tagging secret computed with Diffie-Hellman key exchange.
export async function computeTaggingSecretPoint(
knownAddress: CompleteAddress,
ivsk: Fq,
externalAddress: AztecAddress,
) {
async function computeTaggingSecretPoint(knownAddress: CompleteAddress, ivsk: Fq, externalAddress: AztecAddress) {
const knownPreaddress = await computePreaddress(await knownAddress.publicKeys.hash(), knownAddress.partialAddress);
// TODO: #8970 - Computation of address point from x coordinate might fail
const externalAddressPoint = await externalAddress.toAddressPoint();
Expand All @@ -139,3 +135,13 @@ export async function computeTaggingSecretPoint(
// computeAddressSecret takes care of selecting the one that leads to a positive y-coordinate, which is the only valid address point
return curve.mul(externalAddressPoint, await computeAddressSecret(knownPreaddress, ivsk));
}

export async function computeAppTaggingSecret(
knownAddress: CompleteAddress,
ivsk: Fq,
externalAddress: AztecAddress,
app: AztecAddress,
) {
const taggingSecretPoint = await computeTaggingSecretPoint(knownAddress, ivsk, externalAddress);
return poseidon2Hash([taggingSecretPoint.x, taggingSecretPoint.y, app]);
}
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