Implement signer

app/components/set-lightning-address-modal/set-lightning-address-modal.tsx

@@ -16,8 +16,8 @@ import useNostrProfile from "@app/hooks/use-nostr-profile"
 // store
 import { useAppDispatch } from "@app/store/redux"
 import { updateUserData } from "@app/store/redux/slices/userSlice"
-import { getSecretKey, setPreferredRelay } from "@app/utils/nostr"
-import { getPublicKey } from "nostr-tools"
+import { setPreferredRelay } from "@app/utils/nostr"
+import { getSigner } from "@app/nostr/signer"
 
 gql`
   mutation userUpdateUsername($input: UserUpdateUsernameInput!) {
@@ -58,9 +58,12 @@ export const SetLightningAddressModal = ({
 
   useEffect(() => {
     async function getNostrPubkey() {
-      let secretKey = await getSecretKey()
-      if (secretKey) setNostrPubkey(getPublicKey(secretKey))
-      else console.warn("NOSTR SECRET KEY NOT FOUND")
+      try {
+        const signer = await getSigner()
+        setNostrPubkey(await signer.getPublicKey())
+      } catch {
+        console.warn("NOSTR SECRET KEY NOT FOUND")
+      }
     }
     getNostrPubkey()
   }, [])
@@ -121,7 +124,7 @@ export const SetLightningAddressModal = ({
         nip05: lnAddress,
       },
     })
-    setPreferredRelay()
+    getSigner().then((signer) => setPreferredRelay(signer)).catch(console.warn)
     if ((data?.userUpdateUsername?.errors ?? []).length > 0) {
       if (data?.userUpdateUsername?.errors[0]?.code === "USERNAME_ERROR") {
         setError(SetAddressError.ADDRESS_UNAVAILABLE)

app/hooks/use-nostr-profile.ts

@@ -4,9 +4,9 @@ import {
   generateSecretKey,
   getPublicKey,
   SimplePool,
-  finalizeEvent,
 } from "nostr-tools"
-import { createContactListEvent, getSecretKey, setPreferredRelay } from "@app/utils/nostr"
+import { createContactListEvent, setPreferredRelay } from "@app/utils/nostr"
+import { getSigner, createSignerFromKey, clearSigner } from "@app/nostr/signer"
 import {
   publishEventToRelays,
   verifyEventOnRelays,
@@ -102,8 +102,11 @@ const useNostrProfile = () => {
       KEYCHAIN_NOSTRCREDS_KEY,
       nostrSecret,
     )
-    await setPreferredRelay(secretKey)
-    await createContactListEvent(secretKey)
+    // Clear the signer singleton so it reloads the newly stored key
+    clearSigner()
+    const signer = createSignerFromKey(secretKey)
+    await setPreferredRelay(signer)
+    await createContactListEvent(signer)
 
     // Generate profile images automatically
     let pictureUrl: string | undefined
@@ -189,7 +192,7 @@ const useNostrProfile = () => {
         created_at: Math.floor(Date.now() / 1000),
       }
 
-      const signedKind0Event = finalizeEvent(kind0Event, secretKey)
+      const signedKind0Event = await signer.signEvent(kind0Event)
       console.log("Profile event signed with ID:", signedKind0Event.id)
 
       // Get appropriate relays and publish
@@ -245,12 +248,9 @@ const useNostrProfile = () => {
     try {
       progressCallback?.("Generating profile picture...")
 
-      const secret = await getSecretKey()
-      if (!secret) {
-        throw new Error("No Nostr profile found. Please create a Nostr profile first.")
-      }
-
-      const pubKey = getPublicKey(secret)
+      const signer = await getSigner()
+      const pubKey = await signer.getPublicKey()
+      const nsec = signer.getSecretKeyNsec ? await signer.getSecretKeyNsec() : ""
 
       // Generate images
       console.log("Generating RoboHash avatar...")
@@ -263,19 +263,11 @@ const useNostrProfile = () => {
       // Upload to nostr.build
       progressCallback?.("Uploading profile picture...")
       console.log("Uploading avatar to nostr.build...")
-      const pictureUrl = await uploadToNostrBuild(
-        avatarUri,
-        nip19.nsecEncode(secret),
-        false,
-      )
+      const pictureUrl = await uploadToNostrBuild(avatarUri, nsec, false)
 
       progressCallback?.("Uploading banner image...")
       console.log("Uploading banner to nostr.build...")
-      const bannerUrl = await uploadToNostrBuild(
-        bannerUri,
-        nip19.nsecEncode(secret),
-        false,
-      )
+      const bannerUrl = await uploadToNostrBuild(bannerUri, nsec, false)
 
       // Update profile with new images
       progressCallback?.("Updating profile...")
@@ -383,19 +375,20 @@ const useNostrProfile = () => {
     const publicRelays = getPublishingRelays("profile")
     console.log(`📡 Will publish to ${publicRelays.length} relays`)
 
-    let secret = await getSecretKey()
-    if (!secret) {
+    let signer
+    try {
+      signer = await getSigner()
+    } catch {
       if (dataAuthed && dataAuthed.me && !dataAuthed.me.npub) {
         console.log("No secret key found, creating new profile with provided content...")
         await saveNewNostrKey(undefined, content)
         console.log("Profile created with images and content, returning early")
-        // Return early - saveNewNostrKey already published the profile with images
         return { successCount: 1, totalRelays: 1, successfulRelays: [] }
       } else {
         throw Error("Could not verify npub")
       }
     }
-    let pubKey = getPublicKey(secret)
+    const pubKey = await signer.getPublicKey()
     console.log(`🔑 Publishing with pubkey: ${pubKey}`)
 
     const kind0Event = {
@@ -406,7 +399,7 @@ const useNostrProfile = () => {
       created_at: Math.floor(Date.now() / 1000),
     }
 
-    const signedKind0Event = finalizeEvent(kind0Event, secret)
+    const signedKind0Event = await signer.signEvent(kind0Event)
     console.log(`✍️ Event signed with id: ${signedKind0Event.id}`)
 
     // Use the new helper function for publishing

app/navigation/stack-param-lists.ts

@@ -154,7 +154,7 @@ export type RootStackParamList = {
   CashoutSuccess: undefined
   EditNostrProfile: undefined
   NostrSettingsScreen: undefined
-  Contacts: { userPrivateKey: string }
+  Contacts: undefined
   SignInViaQRCode: undefined
   Nip29GroupChat: { groupId: string }
 }
@@ -164,8 +164,8 @@ export type ChatStackParamList = {
   chatDetail: { chat: Chat; giftwraps: Event[] }
   sendBitcoinDestination: { username: string }
   transactionDetail: { txid: string }
-  messages: { userPrivateKey: string; groupId: string }
-  contactDetails: { contactPubkey: string; userPrivateKey: string }
+  messages: { groupId: string }
+  contactDetails: { contactPubkey: string }
 }
 
 export type ContactStackParamList = {

app/nostr/runtime/SubscriptionRegistry.ts

@@ -6,6 +6,7 @@ type SubscriptionEntry = {
   filter: Filter
   closer: SubCloser
   refCount: number
+  onEvent: (event: Event) => void
 }
 
 export class SubscriptionRegistry {
@@ -45,6 +46,7 @@ export class SubscriptionRegistry {
       filter,
       closer,
       refCount: 1,
+      onEvent,
     })
   }
 
@@ -62,7 +64,7 @@ export class SubscriptionRegistry {
   restore() {
     for (const [key, sub] of this.subs.entries()) {
       const closer = this.relayManager.subscribe(sub.filter, {
-        onevent: () => {},
+        onevent: sub.onEvent,
       })
 
       sub.closer = closer

app/nostr/signer/index.ts

@@ -0,0 +1,39 @@
+import { nip19 } from "nostr-tools"
+import { fetchSecretFromLocalStorage } from "@app/utils/nostr"
+import { LocalSigner } from "./localSigner"
+import { NostrSigner } from "./types"
+
+let signer: NostrSigner | null = null
+let initializing: Promise<NostrSigner> | null = null
+
+export async function getSigner(): Promise<NostrSigner> {
+  if (signer) return signer
+
+  if (!initializing) {
+    initializing = (async () => {
+      const nsec = await fetchSecretFromLocalStorage()
+      if (!nsec) throw new Error("No signer available")
+
+      const { data } = nip19.decode(nsec)
+      signer = new LocalSigner(data as Uint8Array)
+      return signer
+    })()
+  }
+
+  return initializing
+}
+
+/**
+ * Creates a temporary signer from a secret key.
+ * Used during key generation before the key is stored.
+ */
+export function createSignerFromKey(sk: Uint8Array): NostrSigner {
+  return new LocalSigner(sk)
+}
+
+export function clearSigner() {
+  signer = null
+  initializing = null
+}
+
+export type { NostrSigner } from "./types"

app/nostr/signer/localSigner.ts

@@ -0,0 +1,46 @@
+import { getPublicKey, finalizeEvent, nip04, nip44, nip19 } from "nostr-tools"
+import { EventTemplate } from "nostr-tools"
+import { NostrSigner } from "./types"
+import { bytesToHex } from "@noble/curves/abstract/utils"
+
+export class LocalSigner implements NostrSigner {
+  constructor(private readonly sk: Uint8Array) {}
+
+  async getPublicKey() {
+    return getPublicKey(this.sk)
+  }
+
+  async signEvent(event: EventTemplate) {
+    return finalizeEvent(event, this.sk)
+  }
+
+  async getSecretKeyNsec() {
+    return nip19.nsecEncode(this.sk)
+  }
+
+  nip04 = {
+    encrypt: async (pubkey: string, plaintext: string) =>
+      nip04.encrypt(this.sk, pubkey, plaintext),
+
+    decrypt: async (pubkey: string, ciphertext: string) =>
+      nip04.decrypt(this.sk, pubkey, ciphertext),
+  }
+
+  nip44 = {
+    encrypt: async (pubkey: string, plaintext: string) => {
+      const conversationKey = nip44.v2.utils.getConversationKey(
+        bytesToHex(this.sk),
+        pubkey,
+      )
+      return nip44.v2.encrypt(plaintext, conversationKey)
+    },
+
+    decrypt: async (pubkey: string, ciphertext: string) => {
+      const conversationKey = nip44.v2.utils.getConversationKey(
+        bytesToHex(this.sk),
+        pubkey,
+      )
+      return nip44.v2.decrypt(ciphertext, conversationKey)
+    },
+  }
+}

app/nostr/signer/types.ts

@@ -0,0 +1,22 @@
+import { Event, EventTemplate } from "nostr-tools"
+
+export interface NostrSigner {
+  getPublicKey(): Promise<string>
+  signEvent(event: EventTemplate): Promise<Event>
+
+  /**
+   * Returns the nsec-encoded secret key for backup/display purposes.
+   * Optional since remote signers (NIP-46) won't have access to the raw key.
+   */
+  getSecretKeyNsec?(): Promise<string>
+
+  nip04: {
+    encrypt(pubkey: string, plaintext: string): Promise<string>
+    decrypt(pubkey: string, ciphertext: string): Promise<string>
+  }
+
+  nip44: {
+    encrypt(pubkey: string, plaintext: string): Promise<string>
+    decrypt(pubkey: string, ciphertext: string): Promise<string>
+  }
+}

app/screens/chat/GroupChat/GroupChatProvider.tsx

@@ -7,9 +7,9 @@ import React, {
   useRef,
   useState,
 } from "react"
-import { Event, finalizeEvent } from "nostr-tools"
+import { Event } from "nostr-tools"
 import { MessageType } from "@flyerhq/react-native-chat-ui"
-import { getSecretKey } from "@app/utils/nostr"
+import { getSigner } from "@app/nostr/signer"
 import { useChatContext } from "../../../screens/chat/chatContext"
 import { nostrRuntime } from "@app/nostr/runtime/NostrRuntime"
 import { pool } from "@app/utils/nostr/pool"
@@ -218,8 +218,7 @@ export const NostrGroupChatProvider: React.FC<NostrGroupChatProviderProps> = ({
     async (text: string) => {
       if (!userPublicKey) throw Error("No user pubkey present")
 
-      const secretKey = await getSecretKey()
-      if (!secretKey) throw Error("Could not get Secret Key")
+      const signer = await getSigner()
 
       const nostrEvent = {
         kind: 9,
@@ -229,7 +228,7 @@ export const NostrGroupChatProvider: React.FC<NostrGroupChatProviderProps> = ({
         pubkey: userPublicKey,
       }
 
-      const signedEvent = finalizeEvent(nostrEvent as any, secretKey)
+      const signedEvent = await signer.signEvent(nostrEvent as any)
       pool.publish(relayUrls, signedEvent)
     },
     [userPublicKey, groupId, relayUrls],
@@ -238,8 +237,7 @@ export const NostrGroupChatProvider: React.FC<NostrGroupChatProviderProps> = ({
   const requestJoin = useCallback(async () => {
     if (!userPublicKey) throw Error("No user pubkey present")
 
-    const secretKey = await getSecretKey()
-    if (!secretKey) throw Error("Could not get Secret Key")
+    const signer = await getSigner()
 
     const joinEvent = {
       kind: 9021,
@@ -249,7 +247,7 @@ export const NostrGroupChatProvider: React.FC<NostrGroupChatProviderProps> = ({
       pubkey: userPublicKey,
     }
 
-    const signedJoinEvent = finalizeEvent(joinEvent as any, secretKey)
+    const signedJoinEvent = await signer.signEvent(joinEvent as any)
     pool.publish(relayUrls, signedJoinEvent)
 
     // Optimistic system note