add password-based unlock as fallback when Touch ID unavailable; PBKDF2 salted hash stored in keychain

apps/desktop/src/lib/components/EvmDashboard.svelte

@@ -50,6 +50,8 @@
 
 	const w = wallet
 	let inputSeed = $state('')
+	let inputPassword = $state('')
+	let inputUnlockPassword = $state('')
 	let apiKeyInput = $state('')
 	let qrDataUrl = $state('')
 	let qrDialogOpen = $state(false)
@@ -89,8 +91,13 @@
 				<Textarea
 					placeholder="Enter your 12 or 24 word seed phrase"
 					bind:value={inputSeed} />
+				<input
+					type="password"
+					placeholder="Set a password (optional, used when Touch ID is unavailable)"
+					class="flex h-8 w-full rounded-md border border-input bg-transparent px-2 py-1 font-mono text-xs"
+					bind:value={inputPassword} />
 				<Button
-					onclick={() => w.saveVault(inputSeed)}
+					onclick={() => w.saveVault(inputSeed, inputPassword || undefined)}
 					disabled={w.loading || !inputSeed.trim()}>
 					{w.loading ? 'Saving...' : 'Save to Keychain'}
 				</Button>
@@ -107,6 +114,7 @@
 			<CardDescription>Your seed is stored in the system keychain</CardDescription>
 		</CardHeader>
 		<CardContent>
+			<div class="flex flex-col gap-3">
 				{#if w.biometricAvailable}
 					<Button
 						onclick={() => w.unlockWithBiometrics()}
@@ -114,11 +122,27 @@
 						<Fingerprint size={16} />
 						{w.loading ? 'Unlocking...' : 'Unlock with Touch ID'}
 					</Button>
-			{:else}
-				<p class="text-muted-foreground text-xs">
-					Touch ID not available on this device
-				</p>
 				{/if}
+				{#if w.passwordSet}
+					<div class="flex gap-2 items-end">
+						<input
+							type="password"
+							placeholder="Enter password"
+							class="flex h-8 w-full rounded-md border border-input bg-transparent px-2 py-1 font-mono text-xs"
+							bind:value={inputUnlockPassword} />
+						<Button
+							onclick={async () => {
+								const ok = await w.unlockWithPassword(inputUnlockPassword)
+								if (!ok) w.error = 'Wrong password'
+								inputUnlockPassword = ''
+							}}
+							disabled={w.loading || !inputUnlockPassword}
+							size="sm">
+							{w.loading ? '...' : 'Unlock'}
+						</Button>
+					</div>
+				{/if}
+			</div>
 			{#if w.error}
 				<p class="mt-3 text-red-500">{w.error}</p>
 			{/if}

apps/desktop/src/lib/states/wallet.svelte.ts

@@ -81,9 +81,19 @@ export const Wallet = () => {
 	let moneroWalletName = $state('')
 	let moneroAccounts = $state<MoneroAccountEntry[]>([])
 	let moneroWallets = $state<string[]>([])
+	let passwordHash = $state('')
 
 	const net = () => networks.find((n) => n.id === network)!
 
+	async function hashPassword(password: string, salt?: string): Promise<{ salt: string; hash: string }> {
+		const s = salt ?? Array.from(crypto.getRandomValues(new Uint8Array(16)), b => b.toString(16).padStart(2, '0')).join('')
+		const enc = new TextEncoder()
+		const key = await crypto.subtle.importKey('raw', enc.encode(password + s), 'PBKDF2', false, ['deriveBits'])
+		const bits = await crypto.subtle.deriveBits({ name: 'PBKDF2', salt: enc.encode(s), iterations: 100_000, hash: 'SHA-256' }, key, 256)
+		const hash = Array.from(new Uint8Array(bits), b => b.toString(16).padStart(2, '0')).join('')
+		return { salt: s, hash }
+	}
+
 	const isMonero = () => network === 'monero'
 
 	const init = async () => {
@@ -100,18 +110,18 @@ export const Wallet = () => {
 		}
 
 		vaultExists = raw !== null && raw !== undefined
+
 		const [key, keyError] = await tryCatch(
-			electrobun.rpc?.request.getSecret({
+			electrobun.rpc.request.getSecret({ service: 'koins', name: 'alchemy_key' }),
-				service: 'koins',
-				name: 'alchemy_key',
-			}),
 		)
-
+		if (keyError) console.log('key error', keyError)
-		if (keyError) {
-			console.log('key error', keyError)
-		}
-
 		if (key) apiKey = key
+
+		const [ph] = await tryCatch(
+			electrobun.rpc.request.getSecret({ service: 'koins', name: 'vault_password' }),
+		)
+		if (ph) passwordHash = ph
+
 		await checkBiometric()
 		ready = true
 	}
@@ -130,7 +140,7 @@ export const Wallet = () => {
 		}
 	}
 
-	const saveVault = async (phrase: string) => {
+	const saveVault = async (phrase: string, password?: string) => {
 		loading = true
 		error = ''
 		try {
@@ -140,6 +150,16 @@ export const Wallet = () => {
 				name: 'vault',
 				value: phrase.trim(),
 			})
+			if (password) {
+				const ph = await hashPassword(password)
+				const raw = JSON.stringify(ph)
+				await electrobun.rpc?.request.setSecret({
+					service: 'koins',
+					name: 'vault_password',
+					value: raw,
+				})
+				passwordHash = raw
+			}
 			seed = phrase.trim()
 			vaultExists = true
 			await refresh()
@@ -164,6 +184,35 @@ export const Wallet = () => {
 			electrobun.rpc.request.biometricAuth({ reason: 'Unlock wallet' }),
 		)
 		if (!authed) return false
+		return loadSeed()
+	}
+
+	const unlockWithPassword = async (password: string) => {
+		if (!passwordHash) return false
+		try {
+			const { salt, hash } = JSON.parse(passwordHash)
+			const { hash: check } = await hashPassword(password, salt)
+			if (check !== hash) return false
+			return await loadSeed()
+		} catch {
+			return false
+		}
+	}
+
+	const setPassword = async (password: string) => {
+		if (!electrobun.rpc) return
+		const ph = await hashPassword(password)
+		const raw = JSON.stringify(ph)
+		await electrobun.rpc.request.setSecret({
+			service: 'koins',
+			name: 'vault_password',
+			value: raw,
+		})
+		passwordHash = raw
+	}
+
+	async function loadSeed() {
+		if (!electrobun.rpc) return false
 		const [raw] = await tryCatch(
 			electrobun.rpc.request.getSecret({
 				service: 'koins',
@@ -417,10 +466,13 @@ export const Wallet = () => {
 		get moneroAccounts() { return moneroAccounts },
 		get moneroWallets() { return moneroWallets },
 		get biometricAvailable() { return biometricAvailable },
+		get passwordSet() { return !!passwordHash },
 		refresh,
 		init,
 		lock,
 		unlockWithBiometrics,
+		unlockWithPassword,
+		setPassword,
 		saveVault,
 		switchNetwork,
 		saveApiKey,