diff --git a/data/sync-utxos.log b/data/sync-utxos.log
index dbe6626..66405ab 100644
--- a/data/sync-utxos.log
+++ b/data/sync-utxos.log
@@ -1,45 +1,3 @@
-  ⏳ Traitement: 200000/225826 UTXOs insérés...
-  ⏳ Traitement: 210000/225826 UTXOs insérés...
-  ⏳ Traitement: 220000/225826 UTXOs insérés...
-💾 Mise à jour des UTXOs dépensés...
-
-📊 Résumé:
-   - UTXOs vérifiés: 61609
-   - UTXOs toujours disponibles: 61609
-   - UTXOs dépensés détectés: 0
-
-📈 Statistiques finales:
-   - Total UTXOs: 68398
-   - Dépensés: 6789
-   - Non dépensés: 61609
-
-✅ Synchronisation terminée
-🔍 Démarrage de la synchronisation des UTXOs dépensés...
-
-📊 UTXOs à vérifier: 61609
-📡 Récupération des UTXOs depuis Bitcoin...
-📊 UTXOs disponibles dans Bitcoin: 225837
-💾 Création de la table temporaire...
-💾 Insertion des UTXOs disponibles par batch...
-  ⏳ Traitement: 10000/225837 UTXOs insérés...
-  ⏳ Traitement: 20000/225837 UTXOs insérés...
-  ⏳ Traitement: 30000/225837 UTXOs insérés...
-  ⏳ Traitement: 40000/225837 UTXOs insérés...
-  ⏳ Traitement: 50000/225837 UTXOs insérés...
-  ⏳ Traitement: 60000/225837 UTXOs insérés...
-  ⏳ Traitement: 70000/225837 UTXOs insérés...
-  ⏳ Traitement: 80000/225837 UTXOs insérés...
-  ⏳ Traitement: 90000/225837 UTXOs insérés...
-  ⏳ Traitement: 100000/225837 UTXOs insérés...
-  ⏳ Traitement: 110000/225837 UTXOs insérés...
-  ⏳ Traitement: 120000/225837 UTXOs insérés...
-  ⏳ Traitement: 130000/225837 UTXOs insérés...
-  ⏳ Traitement: 140000/225837 UTXOs insérés...
-  ⏳ Traitement: 150000/225837 UTXOs insérés...
-  ⏳ Traitement: 160000/225837 UTXOs insérés...
-  ⏳ Traitement: 170000/225837 UTXOs insérés...
-  ⏳ Traitement: 180000/225837 UTXOs insérés...
-  ⏳ Traitement: 190000/225837 UTXOs insérés...
   ⏳ Traitement: 200000/225837 UTXOs insérés...
   ⏳ Traitement: 210000/225837 UTXOs insérés...
   ⏳ Traitement: 220000/225837 UTXOs insérés...
@@ -98,3 +56,45 @@
    - Non dépensés: 61609
 
 ✅ Synchronisation terminée
+🔍 Démarrage de la synchronisation des UTXOs dépensés...
+
+📊 UTXOs à vérifier: 61598
+📡 Récupération des UTXOs depuis Bitcoin...
+📊 UTXOs disponibles dans Bitcoin: 225867
+💾 Création de la table temporaire...
+💾 Insertion des UTXOs disponibles par batch...
+  ⏳ Traitement: 10000/225867 UTXOs insérés...
+  ⏳ Traitement: 20000/225867 UTXOs insérés...
+  ⏳ Traitement: 30000/225867 UTXOs insérés...
+  ⏳ Traitement: 40000/225867 UTXOs insérés...
+  ⏳ Traitement: 50000/225867 UTXOs insérés...
+  ⏳ Traitement: 60000/225867 UTXOs insérés...
+  ⏳ Traitement: 70000/225867 UTXOs insérés...
+  ⏳ Traitement: 80000/225867 UTXOs insérés...
+  ⏳ Traitement: 90000/225867 UTXOs insérés...
+  ⏳ Traitement: 100000/225867 UTXOs insérés...
+  ⏳ Traitement: 110000/225867 UTXOs insérés...
+  ⏳ Traitement: 120000/225867 UTXOs insérés...
+  ⏳ Traitement: 130000/225867 UTXOs insérés...
+  ⏳ Traitement: 140000/225867 UTXOs insérés...
+  ⏳ Traitement: 150000/225867 UTXOs insérés...
+  ⏳ Traitement: 160000/225867 UTXOs insérés...
+  ⏳ Traitement: 170000/225867 UTXOs insérés...
+  ⏳ Traitement: 180000/225867 UTXOs insérés...
+  ⏳ Traitement: 190000/225867 UTXOs insérés...
+  ⏳ Traitement: 200000/225867 UTXOs insérés...
+  ⏳ Traitement: 210000/225867 UTXOs insérés...
+  ⏳ Traitement: 220000/225867 UTXOs insérés...
+💾 Mise à jour des UTXOs dépensés...
+
+📊 Résumé:
+   - UTXOs vérifiés: 61598
+   - UTXOs toujours disponibles: 61598
+   - UTXOs dépensés détectés: 0
+
+📈 Statistiques finales:
+   - Total UTXOs: 68398
+   - Dépensés: 6800
+   - Non dépensés: 61598
+
+✅ Synchronisation terminée
diff --git a/userwallet/src/components/LoginScreen.tsx b/userwallet/src/components/LoginScreen.tsx
index bf6f340..703f3c4 100644
--- a/userwallet/src/components/LoginScreen.tsx
+++ b/userwallet/src/components/LoginScreen.tsx
@@ -272,14 +272,14 @@ export function LoginScreen(): JSX.Element {
           );
           const endpoints = relays.map((r) => r.endpoint);
           // Boucle de collecte : fetch signatures par hash jusqu'à satisfaction ou timeout
-          merged = await runCollectLoop(
-            endpoints,
-            proof.challenge.hash,
-            proof.signatures,
-            loginPath,
+          merged = await runCollectLoop({
+            relayEndpoints: endpoints,
+            hash: proof.challenge.hash,
+            ourSigs: proof.signatures,
+            path: loginPath,
             pairToMembers,
             pubkeyToPair,
-            {
+            opts: {
               pollMs: COLLECT_POLL_MS,
               timeoutMs: COLLECT_TIMEOUT_MS,
               onProgress: (m) => {
@@ -290,7 +290,7 @@ export function LoginScreen(): JSX.Element {
                 });
               },
             },
-          );
+          });
         } finally {
           setIsCollecting(false);
           setCollectProgressState(null);
@@ -884,14 +884,14 @@ export function LoginScreen(): JSX.Element {
                         identity?.publicKey ?? '',
                         loginPath.pairs_attendus,
                       );
-                      const merged = await runCollectLoop(
-                        endpoints,
-                        proof.challenge.hash,
-                        proof.signatures,
-                        loginPath,
+                      const merged = await runCollectLoop({
+                        relayEndpoints: endpoints,
+                        hash: proof.challenge.hash,
+                        ourSigs: proof.signatures,
+                        path: loginPath,
                         pairToMembers,
                         pubkeyToPair,
-                        {
+                        opts: {
                           pollMs: COLLECT_POLL_MS,
                           timeoutMs: COLLECT_TIMEOUT_MS,
                           onProgress: (m) => {
@@ -902,7 +902,7 @@ export function LoginScreen(): JSX.Element {
                             });
                           },
                         },
-                      );
+                      });
                       setCollectedMerged(merged);
                     } finally {
                       setIsCollecting(false);
diff --git a/userwallet/src/components/PairingDisplayScreen.tsx b/userwallet/src/components/PairingDisplayScreen.tsx
index f71b930..555d202 100644
--- a/userwallet/src/components/PairingDisplayScreen.tsx
+++ b/userwallet/src/components/PairingDisplayScreen.tsx
@@ -89,15 +89,15 @@ export function PairingDisplayScreen(): JSX.Element {
       }
       setIsConfirming(true);
       try {
-        const ok = await runDevice2Confirmation(
-          local.uuid,
-          remote.uuid,
+        const ok = await runDevice2Confirmation({
+          pairLocal: local.uuid,
+          pairRemote: remote.uuid,
           identity,
           relays,
-          identity.t0_anniversaire,
-          Date.now(),
-          pubkeyHex,
-        );
+          start: identity.t0_anniversaire,
+          end: Date.now(),
+          remotePublicKey: pubkeyHex,
+        });
         setJustConnected(ok);
       } catch (err) {
         console.error('Pairing confirmation (device 2):', err);
diff --git a/userwallet/src/components/PairingSetupBlock.tsx b/userwallet/src/components/PairingSetupBlock.tsx
index e9e8146..af3f888 100644
--- a/userwallet/src/components/PairingSetupBlock.tsx
+++ b/userwallet/src/components/PairingSetupBlock.tsx
@@ -94,13 +94,13 @@ export function PairingSetupBlock(): JSX.Element {
     }
     setIsConfirming(true);
     try {
-      await runDevice1Confirmation(
-        local.uuid,
-        remote.uuid,
+      await runDevice1Confirmation({
+        pairLocal: local.uuid,
+        pairRemote: remote.uuid,
         identity,
         relays,
-        pubkeyHex,
-      );
+        remotePublicKey: pubkeyHex,
+      });
     } catch (err) {
       console.error('Pairing confirmation (device 1):', err);
       setRemoteError(
diff --git a/userwallet/src/components/SyncScreen.tsx b/userwallet/src/components/SyncScreen.tsx
index 5b0e62d..3cdc88e 100644
--- a/userwallet/src/components/SyncScreen.tsx
+++ b/userwallet/src/components/SyncScreen.tsx
@@ -57,15 +57,15 @@ export function SyncScreen(): JSX.Element {
         remote !== undefined &&
         identity.privateKey !== undefined
       ) {
-        void checkPairingConfirmationFromSync(
+        void checkPairingConfirmationFromSync({
           relays,
-          local.uuid,
-          remote.uuid,
+          pairLocal: local.uuid,
+          pairRemote: remote.uuid,
           identity,
           start,
           end,
-          remote.publicKey,
-        ).catch((err: unknown) => {
+          remotePublicKey: remote.publicKey,
+        }).catch((err: unknown) => {
           console.error('Pairing confirmation check during sync:', err);
         });
       }
diff --git a/userwallet/src/main.tsx b/userwallet/src/main.tsx
index b2bc486..29dfc6c 100644
--- a/userwallet/src/main.tsx
+++ b/userwallet/src/main.tsx
@@ -3,7 +3,11 @@ import ReactDOM from 'react-dom/client';
 import { App } from './App';
 import './index.css';
 
-ReactDOM.createRoot(document.getElementById('root')!).render(
+const rootElement = document.getElementById('root');
+if (rootElement === null) {
+  throw new Error('Root element not found');
+}
+ReactDOM.createRoot(rootElement).render(
   <React.StrictMode>
     <App />
   </React.StrictMode>,
diff --git a/userwallet/src/services/pairingConfirm.ts b/userwallet/src/services/pairingConfirm.ts
index 2d09390..c3bcc33 100644
--- a/userwallet/src/services/pairingConfirm.ts
+++ b/userwallet/src/services/pairingConfirm.ts
@@ -171,17 +171,22 @@ function buildMsgCle(
   };
 }
 
+interface PublishPairingMessageParams {
+  relays: RelayConfig[];
+  message: MembreFinaliserMessage;
+  hash: string;
+  recipientPublicKey: string;
+  senderIdentity: LocalIdentity;
+}
+
 /**
  * Publish a pairing message (MsgChiffre) to relays.
  * DH obligatoire: encrypt with ECDH and POST MsgCle. recipientPublicKey and senderIdentity required.
  */
 async function publishPairingMessage(
-  relays: RelayConfig[],
-  message: MembreFinaliserMessage,
-  hash: string,
-  recipientPublicKey: string,
-  senderIdentity: LocalIdentity,
+  params: PublishPairingMessageParams,
 ): Promise<void> {
+  const { relays, message, hash, recipientPublicKey, senderIdentity } = params;
   if (recipientPublicKey === undefined || recipientPublicKey === '') {
     throw new Error(
       'Pairing DH obligatoire : clé publique du pair distant requise (exiger publicKey).',
@@ -212,25 +217,31 @@ async function publishPairingMessage(
   }
 }
 
+interface PublishPairingMessageAndSignatureParams {
+  relays: RelayConfig[];
+  message: MembreFinaliserMessage;
+  hash: string;
+  sig: Signature;
+  recipientPublicKey: string;
+  senderIdentity: LocalIdentity;
+}
+
 /**
  * Publish message and first signature to relays.
  * DH obligatoire: recipientPublicKey and senderIdentity required.
  */
 export async function publishPairingMessageAndSignature(
-  relays: RelayConfig[],
-  message: MembreFinaliserMessage,
-  hash: string,
-  sig: Signature,
-  recipientPublicKey: string,
-  senderIdentity: LocalIdentity,
+  params: PublishPairingMessageAndSignatureParams,
 ): Promise<void> {
-  await publishPairingMessage(
+  const { relays, message, hash, sig, recipientPublicKey, senderIdentity } =
+    params;
+  await publishPairingMessage({
     relays,
     message,
     hash,
     recipientPublicKey,
     senderIdentity,
-  );
+  });
   const enabled = relays.filter((r) => r.enabled);
   const msgSig: MsgSignature = { signature: sig };
   for (const r of enabled) {
@@ -255,19 +266,32 @@ export async function publishPairingSignature(
   }
 }
 
+interface FetchPairingMessageParams {
+  relays: RelayConfig[];
+  pairLocal: string;
+  pairRemote: string;
+  start: number;
+  end: number;
+  senderPublicKey?: string;
+  ourIdentity?: LocalIdentity;
+}
+
 /**
  * Fetch messages in time window, find "membre finaliser" v1 for our pairs.
  * DH only: ECDH decryption when senderPublicKey and ourIdentity provided. No base64.
  */
 export async function fetchPairingMessage(
-  relays: RelayConfig[],
-  pairLocal: string,
-  pairRemote: string,
-  start: number,
-  end: number,
-  senderPublicKey?: string,
-  ourIdentity?: LocalIdentity,
+  params: FetchPairingMessageParams,
 ): Promise<{ message: MembreFinaliserMessage; hash: string } | null> {
+  const {
+    relays,
+    pairLocal,
+    pairRemote,
+    start,
+    end,
+    senderPublicKey,
+    ourIdentity,
+  } = params;
   const enabled = relays.filter((r) => r.enabled);
   const key = sortedPairKey(pairLocal, pairRemote);
   const useEcdh =
@@ -401,13 +425,13 @@ async function buildAndPublishPairingVersion2(
   };
   const canonical = JSON.stringify(m2);
   const hash2 = await hashStringAsync(canonical, 'sha256');
-  await publishPairingMessage(
+  await publishPairingMessage({
     relays,
-    m2,
-    hash2,
+    message: m2,
+    hash: hash2,
     recipientPublicKey,
     senderIdentity,
-  );
+  });
 }
 
 /**
@@ -456,17 +480,22 @@ function delay(ms: number): Promise<void> {
   });
 }
 
+interface RunDevice1ConfirmationParams {
+  pairLocal: string;
+  pairRemote: string;
+  identity: LocalIdentity;
+  relays: RelayConfig[];
+  remotePublicKey: string;
+}
+
 /**
  * Run confirmation flow for device 1: create M, sign, publish, poll for remote sig, store.
  * remotePublicKey: identity public key of device 2, for ECDH encryption. Required (DH obligatoire).
  */
 export async function runDevice1Confirmation(
-  pairLocal: string,
-  pairRemote: string,
-  identity: LocalIdentity,
-  relays: RelayConfig[],
-  remotePublicKey: string,
+  params: RunDevice1ConfirmationParams,
 ): Promise<boolean> {
+  const { pairLocal, pairRemote, identity, relays, remotePublicKey } = params;
   if (remotePublicKey === undefined || remotePublicKey === '') {
     throw new Error(
       'Pairing DH obligatoire : clé publique du pair distant requise (exiger publicKey).',
@@ -479,14 +508,14 @@ export async function runDevice1Confirmation(
   );
   const n = generateUuid();
   const sig = signMembreFinaliser(hash, identity, n);
-  await publishPairingMessageAndSignature(
+  await publishPairingMessageAndSignature({
     relays,
     message,
     hash,
     sig,
-    remotePublicKey,
-    identity,
-  );
+    recipientPublicKey: remotePublicKey,
+    senderIdentity: identity,
+  });
   for (let i = 0; i < POLL_ATTEMPTS; i++) {
     if (i > 0) {
       await delay(POLL_DELAY_MS);
@@ -508,28 +537,41 @@ export async function runDevice1Confirmation(
   return false;
 }
 
+interface RunDevice2ConfirmationParams {
+  pairLocal: string;
+  pairRemote: string;
+  identity: LocalIdentity;
+  relays: RelayConfig[];
+  start: number;
+  end: number;
+  remotePublicKey?: string;
+}
+
 /**
  * Run confirmation flow for device 2: fetch M, verify sig1, sign, publish sig2, store.
  * remotePublicKey: identity public key of device 1 (sender), for ECDH decryption.
  */
 export async function runDevice2Confirmation(
-  pairLocal: string,
-  pairRemote: string,
-  identity: LocalIdentity,
-  relays: RelayConfig[],
-  start: number,
-  end: number,
-  remotePublicKey?: string,
+  params: RunDevice2ConfirmationParams,
 ): Promise<boolean> {
-  const found = await fetchPairingMessage(
+  const {
+    pairLocal,
+    pairRemote,
+    identity,
+    relays,
+    start,
+    end,
+    remotePublicKey,
+  } = params;
+  const found = await fetchPairingMessage({
     relays,
     pairLocal,
     pairRemote,
     start,
     end,
-    remotePublicKey,
-    identity,
-  );
+    senderPublicKey: remotePublicKey,
+    ourIdentity: identity,
+  });
   if (found === null) {
     return false;
   }
@@ -547,33 +589,46 @@ export async function runDevice2Confirmation(
   return true;
 }
 
+interface CheckPairingConfirmationFromSyncParams {
+  relays: RelayConfig[];
+  pairLocal: string;
+  pairRemote: string;
+  identity: LocalIdentity;
+  start: number;
+  end: number;
+  remotePublicKey?: string;
+}
+
 /**
  * Check for pairing confirmation during Sync (device 1 timed out, user runs Sync later).
  * Fetches pairing message v1, signatures; if both signers present, stores confirmation.
  * remotePublicKey: identity public key of the other device (sender), for ECDH decryption.
  */
 export async function checkPairingConfirmationFromSync(
-  relays: RelayConfig[],
-  pairLocal: string,
-  pairRemote: string,
-  identity: LocalIdentity,
-  start: number,
-  end: number,
-  remotePublicKey?: string,
+  params: CheckPairingConfirmationFromSyncParams,
 ): Promise<boolean> {
+  const {
+    relays,
+    pairLocal,
+    pairRemote,
+    identity,
+    start,
+    end,
+    remotePublicKey,
+  } = params;
   const already = await getPairingConfirmed(pairLocal, pairRemote);
   if (already) {
     return true;
   }
-  const found = await fetchPairingMessage(
+  const found = await fetchPairingMessage({
     relays,
     pairLocal,
     pairRemote,
     start,
     end,
-    remotePublicKey,
-    identity,
-  );
+    senderPublicKey: remotePublicKey,
+    ourIdentity: identity,
+  });
   if (found === null) {
     return false;
   }
diff --git a/userwallet/src/utils/bip32.ts b/userwallet/src/utils/bip32.ts
index a879375..f9e66dd 100644
--- a/userwallet/src/utils/bip32.ts
+++ b/userwallet/src/utils/bip32.ts
@@ -273,8 +273,18 @@ export function uuidToBip32Words(uuid: string): string[] {
   const uuidBytes = hexToBytes(uuid.replace(/-/g, ''));
   const words: string[] = [];
   for (let i = 0; i < uuidBytes.length; i += 2) {
-    const index = (uuidBytes[i]! << 8) | (uuidBytes[i + 1] ?? 0);
-    words.push(BIP32_WORDLIST[index % BIP32_WORDLIST.length]!);
+    const byte1 = uuidBytes[i];
+    if (byte1 === undefined) {
+      continue;
+    }
+    const byte2 = uuidBytes[i + 1] ?? 0;
+    const index = (byte1 << 8) | byte2;
+    const wordIndex = index % BIP32_WORDLIST.length;
+    const word = BIP32_WORDLIST[wordIndex];
+    if (word === undefined) {
+      continue;
+    }
+    words.push(word);
   }
   return words;
 }
@@ -294,8 +304,12 @@ export function bip32WordsToUuid(words: string[]): string | null {
     }
     const bytes = new Uint8Array(indices.length * 2);
     for (let i = 0; i < indices.length; i++) {
-      bytes[i * 2] = (indices[i]! >> 8) & 0xff;
-      bytes[i * 2 + 1] = indices[i]! & 0xff;
+      const index = indices[i];
+      if (index === undefined) {
+        continue;
+      }
+      bytes[i * 2] = (index >> 8) & 0xff;
+      bytes[i * 2 + 1] = index & 0xff;
     }
     const hex = bytesToHex(bytes);
     return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20, 32)}`;
diff --git a/userwallet/src/utils/collectSignatures.ts b/userwallet/src/utils/collectSignatures.ts
index d757a9c..dfc5231 100644
--- a/userwallet/src/utils/collectSignatures.ts
+++ b/userwallet/src/utils/collectSignatures.ts
@@ -151,19 +151,32 @@ export interface CollectLoopOpts {
   onProgress?: (merged: ProofSignature[]) => void;
 }
 
+interface RunCollectLoopParams {
+  relayEndpoints: string[];
+  hash: string;
+  ourSigs: ProofSignature[];
+  path: LoginPath;
+  pairToMembers: Map<string, string[]>;
+  pubkeyToPair: Map<string, string>;
+  opts: CollectLoopOpts;
+}
+
 /**
  * Collect signatures from relays until we have enough per member, or timeout.
  * Optional onProgress called each poll for UI (e.g. X/Y signatures).
  */
 export async function runCollectLoop(
-  relayEndpoints: string[],
-  hash: string,
-  ourSigs: ProofSignature[],
-  path: LoginPath,
-  pairToMembers: Map<string, string[]>,
-  pubkeyToPair: Map<string, string>,
-  opts: CollectLoopOpts,
+  params: RunCollectLoopParams,
 ): Promise<ProofSignature[]> {
+  const {
+    relayEndpoints,
+    hash,
+    ourSigs,
+    path,
+    pairToMembers,
+    pubkeyToPair,
+    opts,
+  } = params;
   const start = Date.now();
   let merged = ourSigs;
   for (;;) {