diff --git a/cspell.json b/cspell.json
index 3059335afc2..0b8d2a27549 100644
--- a/cspell.json
+++ b/cspell.json
@@ -275,11 +275,12 @@
     "unexcluded",
     "unfinalised",
     "unprefixed",
+    "unshift",
+    "unshifted",
+    "unsynched",
     "unzipit",
     "updateable",
     "upperfirst",
-    "unshift",
-    "unshifted",
     "usecase",
     "usecases",
     "utxo",
@@ -323,5 +324,7 @@
     "lib",
     "*.cmake"
   ],
-  "flagWords": ["anonymous"]
+  "flagWords": [
+    "anonymous"
+  ]
 }
diff --git a/noir-projects/aztec-nr/aztec/src/encrypted_logs/payload.nr b/noir-projects/aztec-nr/aztec/src/encrypted_logs/payload.nr
index 751d3c2d718..1b396ef7b65 100644
--- a/noir-projects/aztec-nr/aztec/src/encrypted_logs/payload.nr
+++ b/noir-projects/aztec-nr/aztec/src/encrypted_logs/payload.nr
@@ -260,7 +260,7 @@ mod test {
             0x25afb798ea6d0b8c1618e50fdeafa463059415013d3b7c75d46abf5e242be70c,
         );
 
-        let _ = OracleMock::mock("getAppTaggingSecretAsSender").returns([69420, 1337]);
+        let _ = OracleMock::mock("getIndexedTaggingSecretAsSender").returns([69420, 1337]);
 
         let _ = OracleMock::mock("incrementAppTaggingSecretIndexAsSender").returns(());
 
diff --git a/noir-projects/aztec-nr/aztec/src/oracle/notes.nr b/noir-projects/aztec-nr/aztec/src/oracle/notes.nr
index 6d2cdab8f83..e7534b14fb9 100644
--- a/noir-projects/aztec-nr/aztec/src/oracle/notes.nr
+++ b/noir-projects/aztec-nr/aztec/src/oracle/notes.nr
@@ -205,25 +205,25 @@ pub unconstrained fn check_nullifier_exists(inner_nullifier: Field) -> bool {
 #[oracle(checkNullifierExists)]
 unconstrained fn check_nullifier_exists_oracle(_inner_nullifier: Field) -> Field {}
 
-/// Same as `get_app_tagging_secret_as_sender`, except it returns the derived tag, ready to be included in a log.
+/// Same as `get_indexed_tagging_secret_as_sender`, except it returns the derived tag, ready to be included in a log.
 pub unconstrained fn get_app_tag_as_sender(sender: AztecAddress, recipient: AztecAddress) -> Field {
-    get_app_tagging_secret_as_sender(sender, recipient).compute_tag(recipient)
+    get_indexed_tagging_secret_as_sender(sender, recipient).compute_tag(recipient)
 }
 
 /// Returns the tagging secret for a given sender and recipient pair, siloed for the current contract address.
 /// Includes the last known index used to send a note tagged with this secret.
-/// For this to work, PXE must know the ivpsk_m of the sender.
+/// For this to work, PXE must know the ivsk_m of the sender.
 /// For the recipient's side, only the address is needed.
-pub unconstrained fn get_app_tagging_secret_as_sender(
+pub unconstrained fn get_indexed_tagging_secret_as_sender(
     sender: AztecAddress,
     recipient: AztecAddress,
 ) -> IndexedTaggingSecret {
-    let result = get_app_tagging_secret_as_sender_oracle(sender, recipient);
+    let result = get_indexed_tagging_secret_as_sender_oracle(sender, recipient);
     IndexedTaggingSecret::deserialize(result)
 }
 
-#[oracle(getAppTaggingSecretAsSender)]
-unconstrained fn get_app_tagging_secret_as_sender_oracle(
+#[oracle(getIndexedTaggingSecretAsSender)]
+unconstrained fn get_indexed_tagging_secret_as_sender_oracle(
     _sender: AztecAddress,
     _recipient: AztecAddress,
 ) -> [Field; INDEXED_TAGGING_SECRET_LENGTH] {}
diff --git a/noir-projects/noir-protocol-circuits/crates/types/src/indexed_tagging_secret.nr b/noir-projects/noir-protocol-circuits/crates/types/src/indexed_tagging_secret.nr
index 89837964cff..4781bd87560 100644
--- a/noir-projects/noir-protocol-circuits/crates/types/src/indexed_tagging_secret.nr
+++ b/noir-projects/noir-protocol-circuits/crates/types/src/indexed_tagging_secret.nr
@@ -6,12 +6,14 @@ pub global INDEXED_TAGGING_SECRET_LENGTH: u32 = 2;
 
 #[derive(Serialize, Deserialize)]
 pub struct IndexedTaggingSecret {
-    secret: Field,
+    app_tagging_secret: Field,
     index: u32,
 }
 
 impl IndexedTaggingSecret {
     pub fn compute_tag(self, recipient: AztecAddress) -> Field {
-        poseidon2_hash([self.secret, recipient.to_field(), self.index as Field])
+        poseidon2_hash(
+            [self.app_tagging_secret, recipient.to_field(), self.index as Field],
+        )
     }
 }
diff --git a/yarn-project/circuits.js/src/keys/derivation.ts b/yarn-project/circuits.js/src/keys/derivation.ts
index 495ea964cf8..032141f9842 100644
--- a/yarn-project/circuits.js/src/keys/derivation.ts
+++ b/yarn-project/circuits.js/src/keys/derivation.ts
@@ -123,7 +123,8 @@ export function deriveKeys(secretKey: Fr) {
   };
 }
 
-export function computeTaggingSecret(knownAddress: CompleteAddress, ivsk: Fq, externalAddress: AztecAddress) {
+// Returns shared tagging secret computed with Diffie-Hellman key exchange.
+export function computeTaggingSecretPoint(knownAddress: CompleteAddress, ivsk: Fq, externalAddress: AztecAddress) {
   const knownPreaddress = computePreaddress(knownAddress.publicKeys.hash(), knownAddress.partialAddress);
   // TODO: #8970 - Computation of address point from x coordinate might fail
   const externalAddressPoint = externalAddress.toAddressPoint();
diff --git a/yarn-project/circuits.js/src/structs/index.ts b/yarn-project/circuits.js/src/structs/index.ts
index 4959a0fb048..9160f7cfe06 100644
--- a/yarn-project/circuits.js/src/structs/index.ts
+++ b/yarn-project/circuits.js/src/structs/index.ts
@@ -15,7 +15,7 @@ export * from './gas_fees.js';
 export * from './gas_settings.js';
 export * from './global_variables.js';
 export * from './block_header.js';
-export * from './tagging_secret.js';
+export * from './indexed_tagging_secret.js';
 export * from './kernel/combined_accumulated_data.js';
 export * from './kernel/combined_constant_data.js';
 export * from './kernel/private_kernel_empty_inputs.js';
diff --git a/yarn-project/circuits.js/src/structs/indexed_tagging_secret.ts b/yarn-project/circuits.js/src/structs/indexed_tagging_secret.ts
new file mode 100644
index 00000000000..4a884180eb8
--- /dev/null
+++ b/yarn-project/circuits.js/src/structs/indexed_tagging_secret.ts
@@ -0,0 +1,40 @@
+import { type AztecAddress } from '@aztec/foundation/aztec-address';
+import { poseidon2Hash } from '@aztec/foundation/crypto';
+import { Fr } from '@aztec/foundation/fields';
+
+export class IndexedTaggingSecret {
+  constructor(public appTaggingSecret: Fr, public index: number) {}
+
+  toFields(): Fr[] {
+    return [this.appTaggingSecret, new Fr(this.index)];
+  }
+
+  static fromFields(serialized: Fr[]) {
+    return new this(serialized[0], serialized[1].toNumber());
+  }
+
+  /**
+   * Computes the tag based on the app tagging secret, recipient and index.
+   * @dev By including the recipient we achieve "directionality" of the tag (when sending a note in the other
+   * direction, the tag will be different).
+   * @param recipient The recipient of the note
+   * @returns The tag.
+   */
+  computeTag(recipient: AztecAddress) {
+    return poseidon2Hash([this.appTaggingSecret, recipient, this.index]);
+  }
+
+  /**
+   * Computes the tag as it is submitted on-chain.
+   * @dev We do this second layer of siloing (one was already done as the tagging secret is app-siloed) because kernels
+   * do that to protect against contract impersonation attacks. This extra layer of siloing in kernels ensures that
+   * a malicious contract cannot emit a note with a tag corresponding to another contract.
+   * @param recipient The recipient of the note
+   * @param app The app address
+   * @returns The tag as it is submitted on-chain in a log.
+   */
+  computeSiloedTag(recipient: AztecAddress, app: AztecAddress) {
+    const tag = this.computeTag(recipient);
+    return poseidon2Hash([app, tag]);
+  }
+}
diff --git a/yarn-project/circuits.js/src/structs/tagging_secret.ts b/yarn-project/circuits.js/src/structs/tagging_secret.ts
deleted file mode 100644
index 97371fe7a8b..00000000000
--- a/yarn-project/circuits.js/src/structs/tagging_secret.ts
+++ /dev/null
@@ -1,24 +0,0 @@
-import { type AztecAddress } from '@aztec/foundation/aztec-address';
-import { poseidon2Hash } from '@aztec/foundation/crypto';
-import { Fr } from '@aztec/foundation/fields';
-
-export class IndexedTaggingSecret {
-  constructor(public secret: Fr, public index: number) {}
-
-  toFields(): Fr[] {
-    return [this.secret, new Fr(this.index)];
-  }
-
-  static fromFields(serialized: Fr[]) {
-    return new this(serialized[0], serialized[1].toNumber());
-  }
-
-  computeTag(recipient: AztecAddress) {
-    return poseidon2Hash([this.secret, recipient, this.index]);
-  }
-
-  computeSiloedTag(recipient: AztecAddress, contractAddress: AztecAddress) {
-    const tag = this.computeTag(recipient);
-    return poseidon2Hash([contractAddress, tag]);
-  }
-}
diff --git a/yarn-project/pxe/src/database/kv_pxe_database.ts b/yarn-project/pxe/src/database/kv_pxe_database.ts
index 5439afa717b..7ff1f19062b 100644
--- a/yarn-project/pxe/src/database/kv_pxe_database.ts
+++ b/yarn-project/pxe/src/database/kv_pxe_database.ts
@@ -585,7 +585,9 @@ export class KVPxeDatabase implements PxeDatabase {
 
   async #setTaggingSecretsIndexes(indexedSecrets: IndexedTaggingSecret[], storageMap: AztecAsyncMap<string, number>) {
     await Promise.all(
-      indexedSecrets.map(indexedSecret => storageMap.set(indexedSecret.secret.toString(), indexedSecret.index)),
+      indexedSecrets.map(indexedSecret =>
+        storageMap.set(indexedSecret.appTaggingSecret.toString(), indexedSecret.index),
+      ),
     );
   }
 
diff --git a/yarn-project/pxe/src/simulator_oracle/index.ts b/yarn-project/pxe/src/simulator_oracle/index.ts
index 0d88946a5ea..160947e25c1 100644
--- a/yarn-project/pxe/src/simulator_oracle/index.ts
+++ b/yarn-project/pxe/src/simulator_oracle/index.ts
@@ -24,7 +24,7 @@ import {
   type L1_TO_L2_MSG_TREE_HEIGHT,
   PrivateLog,
   computeAddressSecret,
-  computeTaggingSecret,
+  computeTaggingSecretPoint,
 } from '@aztec/circuits.js';
 import { type FunctionArtifact, getFunctionArtifact } from '@aztec/foundation/abi';
 import { poseidon2Hash } from '@aztec/foundation/crypto';
@@ -38,6 +38,7 @@ import { type IncomingNoteDao } from '../database/incoming_note_dao.js';
 import { type PxeDatabase } from '../database/index.js';
 import { produceNoteDaos } from '../note_decryption_utils/produce_note_daos.js';
 import { getAcirSimulator } from '../simulator/index.js';
+import { getInitialIndexes, getLeftMostIndexedTaggingSecrets, getRightMostIndexes } from './tagging_utils.js';
 
 /**
  * A data oracle that provides information needed for simulating a transaction.
@@ -257,28 +258,28 @@ export class SimulatorOracle implements DBOracle {
   }
 
   /**
-   * Returns the tagging secret for a given sender and recipient pair. For this to work, the ivpsk_m of the sender must be known.
+   * Returns the tagging secret for a given sender and recipient pair. For this to work, the ivsk_m of the sender must be known.
    * Includes the next index to be used used for tagging with this secret.
    * @param contractAddress - The contract address to silo the secret for
    * @param sender - The address sending the note
    * @param recipient - The address receiving the note
-   * @returns A siloed tagging secret that can be used to tag notes.
+   * @returns An indexed tagging secret that can be used to tag notes.
    */
-  public async getAppTaggingSecretAsSender(
+  public async getIndexedTaggingSecretAsSender(
     contractAddress: AztecAddress,
     sender: AztecAddress,
     recipient: AztecAddress,
   ): Promise<IndexedTaggingSecret> {
     await this.syncTaggedLogsAsSender(contractAddress, sender, recipient);
 
-    const secret = await this.#calculateTaggingSecret(contractAddress, sender, recipient);
-    const [index] = await this.db.getTaggingSecretsIndexesAsSender([secret]);
+    const appTaggingSecret = await this.#calculateAppTaggingSecret(contractAddress, sender, recipient);
+    const [index] = await this.db.getTaggingSecretsIndexesAsSender([appTaggingSecret]);
 
-    return new IndexedTaggingSecret(secret, index);
+    return new IndexedTaggingSecret(appTaggingSecret, index);
   }
 
   /**
-   * Increments the tagging secret for a given sender and recipient pair. For this to work, the ivpsk_m of the sender must be known.
+   * Increments the tagging secret for a given sender and recipient pair. For this to work, the ivsk_m of the sender must be known.
    * @param contractAddress - The contract address to silo the secret for
    * @param sender - The address sending the note
    * @param recipient - The address receiving the note
@@ -288,7 +289,7 @@ export class SimulatorOracle implements DBOracle {
     sender: AztecAddress,
     recipient: AztecAddress,
   ): Promise<void> {
-    const secret = await this.#calculateTaggingSecret(contractAddress, sender, recipient);
+    const secret = await this.#calculateAppTaggingSecret(contractAddress, sender, recipient);
     const contractName = await this.contractDataOracle.getDebugContractName(contractAddress);
     this.log.debug(`Incrementing app tagging secret at ${contractName}(${contractAddress})`, {
       secret,
@@ -302,25 +303,25 @@ export class SimulatorOracle implements DBOracle {
     await this.db.setTaggingSecretsIndexesAsSender([new IndexedTaggingSecret(secret, index + 1)]);
   }
 
-  async #calculateTaggingSecret(contractAddress: AztecAddress, sender: AztecAddress, recipient: AztecAddress) {
+  async #calculateAppTaggingSecret(contractAddress: AztecAddress, sender: AztecAddress, recipient: AztecAddress) {
     const senderCompleteAddress = await this.getCompleteAddress(sender);
     const senderIvsk = await this.keyStore.getMasterIncomingViewingSecretKey(sender);
-    const sharedSecret = computeTaggingSecret(senderCompleteAddress, senderIvsk, recipient);
-    // Silo the secret to the app so it can't be used to track other app's notes
-    const siloedSecret = poseidon2Hash([sharedSecret.x, sharedSecret.y, contractAddress]);
-    return siloedSecret;
+    const secretPoint = 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;
   }
 
   /**
-   * Returns the siloed tagging secrets for a given recipient and all the senders in the address book
+   * Returns the indexed tagging secrets for a given recipient and all the senders in the address book
    * This method should be exposed as an oracle call to allow aztec.nr to perform the orchestration
    * of the syncTaggedLogs and processTaggedLogs methods. However, it is not possible to do so at the moment,
    * so we're keeping it private for now.
    * @param contractAddress - The contract address to silo the secret for
    * @param recipient - The address receiving the notes
-   * @returns A list of siloed tagging secrets
+   * @returns A list of indexed tagging secrets
    */
-  async #getAppTaggingSecretsForContacts(
+  async #getIndexedTaggingSecretsForContacts(
     contractAddress: AztecAddress,
     recipient: AztecAddress,
   ): Promise<IndexedTaggingSecret[]> {
@@ -332,7 +333,7 @@ export class SimulatorOracle implements DBOracle {
       (address, index, self) => index === self.findIndex(otherAddress => otherAddress.equals(address)),
     );
     const appTaggingSecrets = contacts.map(contact => {
-      const sharedSecret = computeTaggingSecret(recipientCompleteAddress, recipientIvsk, contact);
+      const sharedSecret = computeTaggingSecretPoint(recipientCompleteAddress, recipientIvsk, contact);
       return poseidon2Hash([sharedSecret.x, sharedSecret.y, contractAddress]);
     });
     const indexes = await this.db.getTaggingSecretsIndexesAsRecipient(appTaggingSecrets);
@@ -351,7 +352,7 @@ export class SimulatorOracle implements DBOracle {
     sender: AztecAddress,
     recipient: AztecAddress,
   ): Promise<void> {
-    const appTaggingSecret = await this.#calculateTaggingSecret(contractAddress, sender, recipient);
+    const appTaggingSecret = await this.#calculateAppTaggingSecret(contractAddress, sender, recipient);
     let [currentIndex] = await this.db.getTaggingSecretsIndexesAsSender([appTaggingSecret]);
 
     const INDEX_OFFSET = 10;
@@ -409,7 +410,8 @@ export class SimulatorOracle implements DBOracle {
 
   /**
    * Synchronizes the logs tagged with scoped addresses and all the senders in the address book.
-   * Returns the unsynched logs and updates the indexes of the secrets used to tag them until there are no more logs to sync.
+   * Returns the unsynched logs and updates the indexes of the secrets used to tag them until there are no more logs
+   * to sync.
    * @param contractAddress - The address of the contract that the logs are tagged for
    * @param recipient - The address of the recipient
    * @returns A list of encrypted logs tagged with the recipient's address
@@ -419,8 +421,12 @@ export class SimulatorOracle implements DBOracle {
     maxBlockNumber: number,
     scopes?: AztecAddress[],
   ): Promise<Map<string, TxScopedL2Log[]>> {
+    // Half the size of the window we slide over the tagging secret indexes.
+    const WINDOW_HALF_SIZE = 10;
+
     const recipients = scopes ? scopes : await this.keyStore.getAccounts();
-    const result = new Map<string, TxScopedL2Log[]>();
+    // A map of never-before-seen logs going from recipient address to logs
+    const newLogsMap = new Map<string, TxScopedL2Log[]>();
     const contractName = await this.contractDataOracle.getDebugContractName(contractAddress);
     for (const recipient of recipients) {
       const logs: TxScopedL2Log[] = [];
@@ -431,56 +437,40 @@ export class SimulatorOracle implements DBOracle {
       // length, since we don't really know the note they correspond to until we decrypt them.
 
       // 1. Get all the secrets for the recipient and sender pairs (#9365)
-      const appTaggingSecrets = await this.#getAppTaggingSecretsForContacts(contractAddress, recipient);
+      const indexedTaggingSecrets = await this.#getIndexedTaggingSecretsForContacts(contractAddress, recipient);
 
       // 1.1 Set up a sliding window with an offset. Chances are the sender might have messed up
-      // and inadvertently incremented their index without use getting any logs (for example, in case
-      // of a revert). If we stopped looking for logs the first time
-      // we receive 0 for a tag, we might never receive anything from that sender again.
-      // Also there's a possibility that we have advanced our index, but the sender has reused it, so
-      // we might have missed some logs. For these reasons, we have to look both back and ahead of the
-      // stored index
-      const INDEX_OFFSET = 10;
-      type SearchState = {
-        currentTagggingSecrets: IndexedTaggingSecret[];
-        maxIndexesToCheck: { [k: string]: number };
-        initialSecretIndexes: { [k: string]: number };
-        secretsToIncrement: { [k: string]: number };
-      };
-      const searchState = appTaggingSecrets.reduce<SearchState>(
-        (acc, appTaggingSecret) => ({
-          // Start looking for logs before the stored index
-          currentTagggingSecrets: acc.currentTagggingSecrets.concat([
-            new IndexedTaggingSecret(appTaggingSecret.secret, Math.max(0, appTaggingSecret.index - INDEX_OFFSET)),
-          ]),
-          // Keep looking for logs beyond the stored index
-          maxIndexesToCheck: {
-            ...acc.maxIndexesToCheck,
-            ...{ [appTaggingSecret.secret.toString()]: appTaggingSecret.index + INDEX_OFFSET },
-          },
-          // Keeps track of the secrets we have to increment in the database
-          secretsToIncrement: {},
-          // Store the initial set of indexes for the secrets
-          initialSecretIndexes: {
-            ...acc.initialSecretIndexes,
-            ...{ [appTaggingSecret.secret.toString()]: appTaggingSecret.index },
-          },
-        }),
-        { currentTagggingSecrets: [], maxIndexesToCheck: {}, secretsToIncrement: {}, initialSecretIndexes: {} },
-      );
-
-      let { currentTagggingSecrets } = searchState;
-      const { maxIndexesToCheck, secretsToIncrement, initialSecretIndexes } = searchState;
-
-      while (currentTagggingSecrets.length > 0) {
+      // and inadvertently incremented their index without us getting any logs (for example, in case
+      // of a revert). If we stopped looking for logs the first time we don't receive any logs for a tag,
+      // we might never receive anything from that sender again.
+      //    Also there's a possibility that we have advanced our index, but the sender has reused it,
+      // so we might have missed some logs. For these reasons, we have to look both back and ahead of
+      // the stored index.
+
+      // App tagging secrets along with an index in a window to check in the current iteration. Called current because
+      // this value will be updated as we iterate through the window.
+      let currentSecrets = getLeftMostIndexedTaggingSecrets(indexedTaggingSecrets, WINDOW_HALF_SIZE);
+      // Right-most indexes in a window to check stored in a key-value map where key is the app tagging secret
+      // and value is the index to check (the right-most index in the window).
+      const rightMostIndexesMap = getRightMostIndexes(indexedTaggingSecrets, WINDOW_HALF_SIZE);
+      // The initial/unmodified indexes of the secrets stored in a key-value map where key is the app tagging secret.
+      const initialIndexesMap = getInitialIndexes(indexedTaggingSecrets);
+      // A map of indexes to increment for secrets for which we have found logs with an index higher than the one
+      // stored.
+      const indexesToIncrementMap: { [k: string]: number } = {};
+
+      while (currentSecrets.length > 0) {
         // 2. Compute tags using the secrets, recipient and index. Obtain logs for each tag (#9380)
-        const currentTags = currentTagggingSecrets.map(taggingSecret =>
-          taggingSecret.computeSiloedTag(recipient, contractAddress),
+        const currentTags = currentSecrets.map(secret =>
+          // We compute the siloed tags since we need the tags as they appear in the log.
+          secret.computeSiloedTag(recipient, contractAddress),
         );
+
+        // Fetch the logs for the tags and iterate over them
         const logsByTags = await this.aztecNode.getLogsByTags(currentTags);
-        const newTaggingSecrets: IndexedTaggingSecret[] = [];
+        const secretsWithNewIndex: IndexedTaggingSecret[] = [];
         logsByTags.forEach((logsByTag, logIndex) => {
-          const { secret: currentSecret, index: currentIndex } = currentTagggingSecrets[logIndex];
+          const { appTaggingSecret: currentSecret, index: currentIndex } = currentSecrets[logIndex];
           const currentSecretAsStr = currentSecret.toString();
           this.log.debug(`Syncing logs for recipient ${recipient} at contract ${contractName}(${contractAddress})`, {
             recipient,
@@ -504,40 +494,46 @@ export class SimulatorOracle implements DBOracle {
             );
             logs.push(...logsByTag);
 
-            if (currentIndex >= initialSecretIndexes[currentSecretAsStr]) {
-              // 3.2. Increment the index for the tags that have logs, provided they're higher than the one
-              // we have stored in the db (#9380)
-              secretsToIncrement[currentSecretAsStr] = newIndex;
-              // 3.3. Slide the window forwards if we have found logs beyond the initial index
-              maxIndexesToCheck[currentSecretAsStr] = currentIndex + INDEX_OFFSET;
+            if (currentIndex >= initialIndexesMap[currentSecretAsStr]) {
+              // 3.2. We found an index higher than the stored/initial one so we update it in the db later on (#9380)
+              indexesToIncrementMap[currentSecretAsStr] = newIndex;
+              // 3.3. We found an index higher than the initial one so we slide the window.
+              rightMostIndexesMap[currentSecretAsStr] = currentIndex + WINDOW_HALF_SIZE;
             }
           }
           // 3.4 Keep increasing the index (inside the window) temporarily for the tags that have no logs
           // There's a chance the sender missed some and we want to catch up
-          if (currentIndex < maxIndexesToCheck[currentSecretAsStr]) {
+          if (currentIndex < rightMostIndexesMap[currentSecretAsStr]) {
             const newTaggingSecret = new IndexedTaggingSecret(currentSecret, currentIndex + 1);
-            newTaggingSecrets.push(newTaggingSecret);
+            secretsWithNewIndex.push(newTaggingSecret);
           }
         });
+
+        // We store the new indexes for the secrets that have logs with an index higher than the one stored.
         await this.db.setTaggingSecretsIndexesAsRecipient(
-          Object.keys(secretsToIncrement).map(
-            secret => new IndexedTaggingSecret(Fr.fromHexString(secret), secretsToIncrement[secret]),
+          Object.keys(indexesToIncrementMap).map(
+            secret => new IndexedTaggingSecret(Fr.fromHexString(secret), indexesToIncrementMap[secret]),
           ),
         );
-        currentTagggingSecrets = newTaggingSecrets;
+
+        // We've processed all the current secret-index pairs so we proceed to the next iteration.
+        currentSecrets = secretsWithNewIndex;
       }
 
-      result.set(
+      newLogsMap.set(
         recipient.toString(),
         // Remove logs with a block number higher than the max block number
         // Duplicates are likely to happen due to the sliding window, so we also filter them out
         logs.filter(
           (log, index, self) =>
+            // The following condition is true if the log has small enough block number and is unique
+            // --> the right side of the && is true if the index of the current log is the first occurrence
+            // of the log in the array --> that way we ensure uniqueness.
             log.blockNumber <= maxBlockNumber && index === self.findIndex(otherLog => otherLog.equals(log)),
         ),
       );
     }
-    return result;
+    return newLogsMap;
   }
 
   /**
diff --git a/yarn-project/pxe/src/simulator_oracle/simulator_oracle.test.ts b/yarn-project/pxe/src/simulator_oracle/simulator_oracle.test.ts
index 930d586681d..1e88eaab363 100644
--- a/yarn-project/pxe/src/simulator_oracle/simulator_oracle.test.ts
+++ b/yarn-project/pxe/src/simulator_oracle/simulator_oracle.test.ts
@@ -18,7 +18,7 @@ import {
   IndexedTaggingSecret,
   MAX_NOTE_HASHES_PER_TX,
   computeAddress,
-  computeTaggingSecret,
+  computeTaggingSecretPoint,
   deriveKeys,
 } from '@aztec/circuits.js';
 import { pedersenHash, poseidon2Hash } from '@aztec/foundation/crypto';
@@ -103,9 +103,9 @@ function computeSiloedTagForIndex(
   contractAddress: AztecAddress,
   index: number,
 ) {
-  const sharedSecret = computeTaggingSecret(sender.completeAddress, sender.ivsk, recipient);
-  const siloedSecret = poseidon2Hash([sharedSecret.x, sharedSecret.y, contractAddress]);
-  const tag = poseidon2Hash([siloedSecret, recipient, index]);
+  const secretPoint = computeTaggingSecretPoint(sender.completeAddress, sender.ivsk, recipient);
+  const appSecret = poseidon2Hash([secretPoint.x, secretPoint.y, contractAddress]);
+  const tag = poseidon2Hash([appSecret, recipient, index]);
   return poseidon2Hash([contractAddress, tag]);
 }
 
@@ -240,12 +240,12 @@ describe('Simulator oracle', () => {
 
       const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
       const secrets = senders.map(sender => {
-        const firstSenderSharedSecret = computeTaggingSecret(recipient, ivsk, sender.completeAddress.address);
-        return poseidon2Hash([firstSenderSharedSecret.x, firstSenderSharedSecret.y, contractAddress]);
+        const firstSenderSecretPoint = computeTaggingSecretPoint(recipient, ivsk, sender.completeAddress.address);
+        return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
       });
 
       // First sender should have 2 logs, but keep index 1 since they were built using the same tag
-      // Next 4 senders hould also have index 1 = offset + 1
+      // Next 4 senders should also have index 1 = offset + 1
       // Last 5 senders should have index 2 = offset + 2
       const indexes = await database.getTaggingSecretsIndexesAsRecipient(secrets);
 
@@ -269,8 +269,8 @@ describe('Simulator oracle', () => {
       // Recompute the secrets (as recipient) to ensure indexes are updated
       const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
       const secrets = senders.map(sender => {
-        const firstSenderSharedSecret = computeTaggingSecret(recipient, ivsk, sender.completeAddress.address);
-        return poseidon2Hash([firstSenderSharedSecret.x, firstSenderSharedSecret.y, contractAddress]);
+        const firstSenderSecretPoint = computeTaggingSecretPoint(recipient, ivsk, sender.completeAddress.address);
+        return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
       });
 
       const indexesAsSender = await database.getTaggingSecretsIndexesAsSender(secrets);
@@ -320,12 +320,12 @@ describe('Simulator oracle', () => {
       // Recompute the secrets (as recipient) to ensure indexes are updated
       const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
       const secrets = senders.map(sender => {
-        const firstSenderSharedSecret = computeTaggingSecret(recipient, ivsk, sender.completeAddress.address);
-        return poseidon2Hash([firstSenderSharedSecret.x, firstSenderSharedSecret.y, contractAddress]);
+        const firstSenderSecretPoint = computeTaggingSecretPoint(recipient, ivsk, sender.completeAddress.address);
+        return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
       });
 
       // First sender should have 2 logs, but keep index 1 since they were built using the same tag
-      // Next 4 senders hould also have index 6 = offset + 1
+      // Next 4 senders should also have index 6 = offset + 1
       // Last 5 senders should have index 7 = offset + 2
       const indexes = await database.getTaggingSecretsIndexesAsRecipient(secrets);
 
@@ -344,8 +344,8 @@ describe('Simulator oracle', () => {
       // Recompute the secrets (as recipient) to update indexes
       const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
       const secrets = senders.map(sender => {
-        const firstSenderSharedSecret = computeTaggingSecret(recipient, ivsk, sender.completeAddress.address);
-        return poseidon2Hash([firstSenderSharedSecret.x, firstSenderSharedSecret.y, contractAddress]);
+        const firstSenderSecretPoint = computeTaggingSecretPoint(recipient, ivsk, sender.completeAddress.address);
+        return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
       });
 
       // Increase our indexes to 2
@@ -377,8 +377,8 @@ describe('Simulator oracle', () => {
       // Recompute the secrets (as recipient) to update indexes
       const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
       const secrets = senders.map(sender => {
-        const firstSenderSharedSecret = computeTaggingSecret(recipient, ivsk, sender.completeAddress.address);
-        return poseidon2Hash([firstSenderSharedSecret.x, firstSenderSharedSecret.y, contractAddress]);
+        const firstSenderSecretPoint = computeTaggingSecretPoint(recipient, ivsk, sender.completeAddress.address);
+        return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
       });
 
       await database.setTaggingSecretsIndexesAsRecipient(
@@ -408,8 +408,8 @@ describe('Simulator oracle', () => {
       // Recompute the secrets (as recipient) to update indexes
       const ivsk = await keyStore.getMasterIncomingViewingSecretKey(recipient.address);
       const secrets = senders.map(sender => {
-        const firstSenderSharedSecret = computeTaggingSecret(recipient, ivsk, sender.completeAddress.address);
-        return poseidon2Hash([firstSenderSharedSecret.x, firstSenderSharedSecret.y, contractAddress]);
+        const firstSenderSecretPoint = computeTaggingSecretPoint(recipient, ivsk, sender.completeAddress.address);
+        return poseidon2Hash([firstSenderSecretPoint.x, firstSenderSecretPoint.y, contractAddress]);
       });
 
       await database.setTaggingSecretsIndexesAsRecipient(
diff --git a/yarn-project/pxe/src/simulator_oracle/tagging_utils.ts b/yarn-project/pxe/src/simulator_oracle/tagging_utils.ts
new file mode 100644
index 00000000000..52ed10a1cfc
--- /dev/null
+++ b/yarn-project/pxe/src/simulator_oracle/tagging_utils.ts
@@ -0,0 +1,54 @@
+import { IndexedTaggingSecret } from '@aztec/circuits.js';
+
+/**
+ * Gets indexed tagging secrets with leftmost indexes.
+ * @param indexedTaggingSecrets - The indexed tagging secrets to get the leftmost indexed tagging secrets from.
+ * @param windowHalfSize- The half size of the window to slide over the tagging secret indexes.
+ * @returns The leftmost indexed tagging secrets.
+ */
+export function getLeftMostIndexedTaggingSecrets(
+  indexedTaggingSecrets: IndexedTaggingSecret[],
+  windowHalfSize: number,
+): IndexedTaggingSecret[] {
+  return indexedTaggingSecrets.map(
+    indexedTaggingSecret =>
+      new IndexedTaggingSecret(
+        indexedTaggingSecret.appTaggingSecret,
+        Math.max(0, indexedTaggingSecret.index - windowHalfSize),
+      ),
+  );
+}
+
+/**
+ * Creates a map from app tagging secret to rightmost index.
+ * @param indexedTaggingSecrets - The indexed tagging secrets to get the rightmost indexes from.
+ * @param windowHalfSize- The half size of the window to slide over the tagging secret indexes.
+ * @returns The map from app tagging secret to rightmost index.
+ */
+export function getRightMostIndexes(
+  indexedTaggingSecrets: IndexedTaggingSecret[],
+  windowHalfSize: number,
+): { [k: string]: number } {
+  const rightMostIndexes: { [k: string]: number } = {};
+
+  for (const indexedTaggingSecret of indexedTaggingSecrets) {
+    rightMostIndexes[indexedTaggingSecret.appTaggingSecret.toString()] = indexedTaggingSecret.index + windowHalfSize;
+  }
+
+  return rightMostIndexes;
+}
+
+/**
+ * Creates a map from app tagging secret to initial index.
+ * @param indexedTaggingSecrets - The indexed tagging secrets to get the initial indexes from.
+ * @returns The map from app tagging secret to initial index.
+ */
+export function getInitialIndexes(indexedTaggingSecrets: IndexedTaggingSecret[]): { [k: string]: number } {
+  const initialIndexes: { [k: string]: number } = {};
+
+  for (const indexedTaggingSecret of indexedTaggingSecrets) {
+    initialIndexes[indexedTaggingSecret.appTaggingSecret.toString()] = indexedTaggingSecret.index;
+  }
+
+  return initialIndexes;
+}
diff --git a/yarn-project/simulator/src/acvm/oracle/oracle.ts b/yarn-project/simulator/src/acvm/oracle/oracle.ts
index 99d5d5f29f2..254b91fb3ab 100644
--- a/yarn-project/simulator/src/acvm/oracle/oracle.ts
+++ b/yarn-project/simulator/src/acvm/oracle/oracle.ts
@@ -375,8 +375,8 @@ export class Oracle {
     this.typedOracle.notifySetMinRevertibleSideEffectCounter(frToNumber(fromACVMField(minRevertibleSideEffectCounter)));
   }
 
-  async getAppTaggingSecretAsSender([sender]: ACVMField[], [recipient]: ACVMField[]): Promise<ACVMField[]> {
-    const taggingSecret = await this.typedOracle.getAppTaggingSecretAsSender(
+  async getIndexedTaggingSecretAsSender([sender]: ACVMField[], [recipient]: ACVMField[]): Promise<ACVMField[]> {
+    const taggingSecret = await this.typedOracle.getIndexedTaggingSecretAsSender(
       AztecAddress.fromString(sender),
       AztecAddress.fromString(recipient),
     );
diff --git a/yarn-project/simulator/src/acvm/oracle/typed_oracle.ts b/yarn-project/simulator/src/acvm/oracle/typed_oracle.ts
index 2505a0478b0..d5c461bd3c2 100644
--- a/yarn-project/simulator/src/acvm/oracle/typed_oracle.ts
+++ b/yarn-project/simulator/src/acvm/oracle/typed_oracle.ts
@@ -237,8 +237,8 @@ export abstract class TypedOracle {
     throw new OracleMethodNotAvailableError('debugLog');
   }
 
-  getAppTaggingSecretAsSender(_sender: AztecAddress, _recipient: AztecAddress): Promise<IndexedTaggingSecret> {
-    throw new OracleMethodNotAvailableError('getAppTaggingSecretAsSender');
+  getIndexedTaggingSecretAsSender(_sender: AztecAddress, _recipient: AztecAddress): Promise<IndexedTaggingSecret> {
+    throw new OracleMethodNotAvailableError('getIndexedTaggingSecretAsSender');
   }
 
   incrementAppTaggingSecretIndexAsSender(_sender: AztecAddress, _recipient: AztecAddress): Promise<void> {
diff --git a/yarn-project/simulator/src/client/db_oracle.ts b/yarn-project/simulator/src/client/db_oracle.ts
index 6702810c86a..9472148257a 100644
--- a/yarn-project/simulator/src/client/db_oracle.ts
+++ b/yarn-project/simulator/src/client/db_oracle.ts
@@ -198,21 +198,21 @@ export interface DBOracle extends CommitmentsDB {
   getBlockNumber(): Promise<number>;
 
   /**
-   * Returns the tagging secret for a given sender and recipient pair. For this to work, the ivpsk_m of the sender must be known.
+   * Returns the tagging secret for a given sender and recipient pair. For this to work, the ivsk_m of the sender must be known.
    * Includes the next index to be used used for tagging with this secret.
    * @param contractAddress - The contract address to silo the secret for
    * @param sender - The address sending the note
    * @param recipient - The address receiving the note
    * @returns A tagging secret that can be used to tag notes.
    */
-  getAppTaggingSecretAsSender(
+  getIndexedTaggingSecretAsSender(
     contractAddress: AztecAddress,
     sender: AztecAddress,
     recipient: AztecAddress,
   ): Promise<IndexedTaggingSecret>;
 
   /**
-   * Increments the tagging secret for a given sender and recipient pair. For this to work, the ivpsk_m of the sender must be known.
+   * Increments the tagging secret for a given sender and recipient pair. For this to work, the ivsk_m of the sender must be known.
    * @param contractAddress - The contract address to silo the secret for
    * @param sender - The address sending the note
    * @param recipient - The address receiving the note
diff --git a/yarn-project/simulator/src/client/private_execution.test.ts b/yarn-project/simulator/src/client/private_execution.test.ts
index 4d225f58d57..19d96f8b043 100644
--- a/yarn-project/simulator/src/client/private_execution.test.ts
+++ b/yarn-project/simulator/src/client/private_execution.test.ts
@@ -233,7 +233,7 @@ describe('Private Execution test suite', () => {
       throw new Error(`Unknown address: ${address}. Recipient: ${recipient}, Owner: ${owner}`);
     });
 
-    oracle.getAppTaggingSecretAsSender.mockImplementation(
+    oracle.getIndexedTaggingSecretAsSender.mockImplementation(
       (_contractAddress: AztecAddress, _sender: AztecAddress, _recipient: AztecAddress) => {
         const secret = Fr.random();
         return Promise.resolve(new IndexedTaggingSecret(secret, 0));
diff --git a/yarn-project/simulator/src/client/view_data_oracle.ts b/yarn-project/simulator/src/client/view_data_oracle.ts
index 358a3271186..bfd870760b1 100644
--- a/yarn-project/simulator/src/client/view_data_oracle.ts
+++ b/yarn-project/simulator/src/client/view_data_oracle.ts
@@ -296,16 +296,16 @@ export class ViewDataOracle extends TypedOracle {
   /**
    * Returns the tagging secret for a given sender and recipient pair, siloed to the current contract address.
    * Includes the next index to be used used for tagging with this secret.
-   * For this to work, the ivpsk_m of the sender must be known.
+   * For this to work, the ivsk_m of the sender must be known.
    * @param sender - The address sending the note
    * @param recipient - The address receiving the note
    * @returns A tagging secret that can be used to tag notes.
    */
-  public override async getAppTaggingSecretAsSender(
+  public override async getIndexedTaggingSecretAsSender(
     sender: AztecAddress,
     recipient: AztecAddress,
   ): Promise<IndexedTaggingSecret> {
-    return await this.db.getAppTaggingSecretAsSender(this.contractAddress, sender, recipient);
+    return await this.db.getIndexedTaggingSecretAsSender(this.contractAddress, sender, recipient);
   }
 
   public override async syncNotes() {
diff --git a/yarn-project/txe/src/oracle/txe_oracle.ts b/yarn-project/txe/src/oracle/txe_oracle.ts
index a455373b83c..03928a58a30 100644
--- a/yarn-project/txe/src/oracle/txe_oracle.ts
+++ b/yarn-project/txe/src/oracle/txe_oracle.ts
@@ -36,7 +36,7 @@ import {
   type PublicDataTreeLeafPreimage,
   type PublicDataWrite,
   computeContractClassId,
-  computeTaggingSecret,
+  computeTaggingSecretPoint,
   deriveKeys,
   getContractClassFromArtifact,
 } from '@aztec/circuits.js';
@@ -890,24 +890,24 @@ export class TXE implements TypedOracle {
   }
 
   async incrementAppTaggingSecretIndexAsSender(sender: AztecAddress, recipient: AztecAddress): Promise<void> {
-    const appSecret = await this.#calculateTaggingSecret(this.contractAddress, sender, recipient);
+    const appSecret = await this.#calculateAppTaggingSecret(this.contractAddress, sender, recipient);
     const [index] = await this.txeDatabase.getTaggingSecretsIndexesAsSender([appSecret]);
     await this.txeDatabase.setTaggingSecretsIndexesAsSender([new IndexedTaggingSecret(appSecret, index + 1)]);
   }
 
-  async getAppTaggingSecretAsSender(sender: AztecAddress, recipient: AztecAddress): Promise<IndexedTaggingSecret> {
-    const secret = await this.#calculateTaggingSecret(this.contractAddress, sender, recipient);
+  async getIndexedTaggingSecretAsSender(sender: AztecAddress, recipient: AztecAddress): Promise<IndexedTaggingSecret> {
+    const secret = await this.#calculateAppTaggingSecret(this.contractAddress, sender, recipient);
     const [index] = await this.txeDatabase.getTaggingSecretsIndexesAsSender([secret]);
     return new IndexedTaggingSecret(secret, index);
   }
 
-  async #calculateTaggingSecret(contractAddress: AztecAddress, sender: AztecAddress, recipient: AztecAddress) {
+  async #calculateAppTaggingSecret(contractAddress: AztecAddress, sender: AztecAddress, recipient: AztecAddress) {
     const senderCompleteAddress = await this.getCompleteAddress(sender);
     const senderIvsk = await this.keyStore.getMasterIncomingViewingSecretKey(sender);
-    const sharedSecret = computeTaggingSecret(senderCompleteAddress, senderIvsk, recipient);
+    const secretPoint = computeTaggingSecretPoint(senderCompleteAddress, senderIvsk, recipient);
     // Silo the secret to the app so it can't be used to track other app's notes
-    const siloedSecret = poseidon2Hash([sharedSecret.x, sharedSecret.y, contractAddress]);
-    return siloedSecret;
+    const appSecret = poseidon2Hash([secretPoint.x, secretPoint.y, contractAddress]);
+    return appSecret;
   }
 
   async syncNotes() {
diff --git a/yarn-project/txe/src/txe_service/txe_service.ts b/yarn-project/txe/src/txe_service/txe_service.ts
index de5c041d1c1..9d87db3c1b4 100644
--- a/yarn-project/txe/src/txe_service/txe_service.ts
+++ b/yarn-project/txe/src/txe_service/txe_service.ts
@@ -584,8 +584,8 @@ export class TXEService {
     return toForeignCallResult([toArray(witness.toFields())]);
   }
 
-  async getAppTaggingSecretAsSender(sender: ForeignCallSingle, recipient: ForeignCallSingle) {
-    const secret = await this.typedOracle.getAppTaggingSecretAsSender(
+  async getIndexedTaggingSecretAsSender(sender: ForeignCallSingle, recipient: ForeignCallSingle) {
+    const secret = await this.typedOracle.getIndexedTaggingSecretAsSender(
       AztecAddress.fromField(fromSingle(sender)),
       AztecAddress.fromField(fromSingle(recipient)),
     );