Encrypt credentials at rest; unify clipboard-link suggestions

Encrypt proxy / youtubePoToken / updateToken on disk via safeStorage (DPAPI on Windows), with a one-time launch migration for legacy plaintext. Decrypted before reaching callers/renderer; backup export still writes clear, as documented. Harden updater token handling to refuse cross-origin redirects on the authenticated REST check.

Extract the clipboard-link logic from DownloadBar into the shared useClipboardLink hook: add an optional filter (library skips single-video links), an offer() for external aerofetch:// / .url links, and a source field driving banner wording. Add looksLikeSingleVideo plus its unit tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/index.ts

@@ -23,7 +23,13 @@ import {
   hasActiveDownloads
 } from './download'
 import { runTerminal, cancelTerminal } from './terminal'
-import { getSettings, setSettings, ensureMediaDirs, applyLaunchAtStartup } from './settings'
+import {
+  getSettings,
+  setSettings,
+  ensureMediaDirs,
+  applyLaunchAtStartup,
+  migrateSecretsAtRest
+} from './settings'
 import { listHistory, addHistory, removeHistory, removeManyHistory, clearHistory } from './history'
 import { listTemplates, saveTemplate, removeTemplate } from './templates'
 import { setupPortableData } from './portable'
@@ -398,6 +404,10 @@ if (isPrimaryInstance) {
     // exist from first launch (downloads are routed into them by kind).
     ensureMediaDirs()
 
+    // Encrypt any credential still stored as legacy plaintext (from before at-rest
+    // encryption), once safeStorage is available post-ready.
+    migrateSecretsAtRest()
+
     // Sync the Windows "run at sign-in" entry with the persisted setting, so it
     // reflects the user's choice even if they changed it on another install.
     applyLaunchAtStartup(getSettings().launchAtStartup)

src/main/settings.ts

@@ -1,4 +1,4 @@
-import { app } from 'electron'
+import { app, safeStorage } from 'electron'
 import { join } from 'path'
 import { mkdirSync } from 'fs'
 import Store from 'electron-store'
@@ -149,6 +149,72 @@ function getStore(): Store<Settings> {
   return store
 }
 
+// --- Credential encryption at rest ------------------------------------------
+// proxy / youtubePoToken / updateToken can carry secrets (a proxy password, API
+// tokens). They're stored encrypted via Electron safeStorage (DPAPI on Windows)
+// so a leaked settings.json doesn't expose them. They're still decrypted before
+// reaching the renderer and exported in clear by backup — this guards the file at
+// rest only.
+const SECRET_KEYS = ['proxy', 'youtubePoToken', 'updateToken'] as const
+
+// Marks a value produced by encryptSecret, so a read can tell ciphertext from a
+// legacy plaintext value (written before encryption existed, or while safeStorage
+// was unavailable) and migrate it on the next write.
+const ENC_PREFIX = 'enc:v1:'
+
+/** Encrypt a secret for storage. Falls back to plaintext where safeStorage is unavailable. */
+function encryptSecret(plain: string): string {
+  if (!plain) return ''
+  try {
+    if (safeStorage.isEncryptionAvailable()) {
+      return ENC_PREFIX + safeStorage.encryptString(plain).toString('base64')
+    }
+  } catch {
+    /* fall through — store plaintext, as it was before encryption existed */
+  }
+  return plain
+}
+
+/** Decrypt a stored secret. Legacy plaintext is returned as-is; an undecryptable blob → ''. */
+function decryptSecret(stored: string): string {
+  if (!stored.startsWith(ENC_PREFIX)) return stored
+  try {
+    return safeStorage.decryptString(Buffer.from(stored.slice(ENC_PREFIX.length), 'base64'))
+  } catch {
+    // Different user/machine or a corrupt blob — drop it rather than surface
+    // ciphertext into the UI or onto a yt-dlp command line.
+    return ''
+  }
+}
+
+/** A copy of settings with the credential fields decrypted for in-process use. */
+function withDecryptedSecrets(raw: Settings): Settings {
+  const out = { ...raw }
+  for (const key of SECRET_KEYS) out[key] = decryptSecret(raw[key] ?? '')
+  return out
+}
+
+/**
+ * One-time (per launch) migration: re-store any credential still held as legacy
+ * plaintext as ciphertext. Lets settings files written before at-rest encryption
+ * get protected without a write on the hot getSettings() path. No-op when there's
+ * nothing to migrate or safeStorage is unavailable.
+ */
+export function migrateSecretsAtRest(): void {
+  let available = false
+  try {
+    available = safeStorage.isEncryptionAvailable()
+  } catch {
+    return
+  }
+  if (!available) return
+  const s = getStore()
+  for (const key of SECRET_KEYS) {
+    const raw = s.get(key) ?? ''
+    if (raw && !raw.startsWith(ENC_PREFIX)) s.set(key, encryptSecret(raw))
+  }
+}
+
 export function getSettings(): Settings {
   const s = getStore()
   // getSettings() is on hot paths (buildCommand, notification checks, the system-
@@ -170,7 +236,9 @@ export function getSettings(): Settings {
   if (!(ACCENT_COLORS as readonly string[]).includes(cur.accentColor)) {
     s.set('accentColor', DEFAULTS.accentColor)
   }
-  return s.store
+  // Hand callers (and, via IPC, the renderer) plaintext credentials — they're
+  // only encrypted on disk (see withDecryptedSecrets / encryptSecret).
+  return withDecryptedSecrets(s.store)
 }
 
 /** Shallow structural equality for DownloadOptions (sponsorBlockCategories compared by value). */
@@ -276,17 +344,20 @@ export function setSettings(partial: Partial<Settings>): Settings {
         break
       case 'defaultVideoQuality':
       case 'defaultAudioQuality':
-      // proxy may carry plaintext credentials (user:pass@host); they are stored
-      // and exported by exportBackup as-is — documented, not masked.
-      case 'proxy':
       case 'rateLimit':
       case 'youtubePlayerClient':
-      case 'youtubePoToken':
         if (typeof value === 'string') s.set(key, value)
         break
+      // Credential-bearing fields — encrypted at rest (see encryptSecret). proxy
+      // may embed user:pass@host; youtubePoToken is an access token. exportBackup
+      // still writes them in clear (via the decrypted getSettings), as documented.
+      case 'proxy':
+      case 'youtubePoToken':
+        if (typeof value === 'string') s.set(key, encryptSecret(value))
+        break
       case 'updateToken':
-        // A Gitea token has no spaces; trim and store as-is (like proxy creds).
+        // A Gitea token has no spaces; trim before encrypting (like proxy creds).
-        if (typeof value === 'string') s.set('updateToken', value.trim())
+        if (typeof value === 'string') s.set('updateToken', encryptSecret(value.trim()))
         break
     }
   }

src/main/updater.ts

@@ -15,8 +15,12 @@ import {
  * Authorization header for the update host. Empty unless the user has set an
  * updateToken in Settings — needed when the release repo is private or the Gitea
  * instance requires sign-in for anonymous access (the default on this instance).
- * Only ever sent to the host-pinned UPDATE_HOST (see isTrustedDownloadUrl), so a
+ *
- * redirect can never leak the token to another origin.
+ * The token must never reach an origin other than the host-pinned UPDATE_HOST.
+ * Every request that carries it guards against that on its own terms: the REST
+ * check refuses to follow redirects (`redirect: 'error'`), and the download paths
+ * use `redirect: 'manual'` and re-validate each hop with isTrustedDownloadUrl. So
+ * a redirect can't bounce the header to another host on any path.
  */
 function authHeader(): Record<string, string> {
   const tok = getSettings().updateToken?.trim()
@@ -123,6 +127,10 @@ export async function checkForAppUpdate(): Promise<AppUpdateInfo> {
   try {
     const res = await fetch(RELEASE_API, {
       headers: { Accept: 'application/json', ...authHeader() },
+      // The API lives at an exact pinned URL and answers 200 directly. Refusing
+      // redirects keeps an authenticated check from ever forwarding the token to
+      // another origin; a stray redirect fails safe into the catch below.
+      redirect: 'error',
       signal: controller.signal
     })
     if (!res.ok) {

src/renderer/src/components/DownloadBar.tsx

@@ -33,18 +33,7 @@ import { sameVideo } from '../store/queueStats'
 import { useSettings } from '../store/settings'
 import { Select } from './Select'
 import { Hint } from './Hint'
-
+import { useClipboardLink, looksLikeUrl } from '../useClipboardLink'
-/** A quick heuristic for "this clipboard text is a link worth offering". */
-function looksLikeUrl(text: string): boolean {
-  const t = text.trim()
-  if (!/^https?:\/\//i.test(t)) return false
-  try {
-    new URL(t)
-    return true
-  } catch {
-    return false
-  }
-}
 
 /** First http(s) URL in a blob of dropped text (one per line; '#' comments skipped). */
 function firstUrl(text: string): string | null {
@@ -384,62 +373,22 @@ export function DownloadBar(): React.JSX.Element {
   // bar's global kind. Lets a playlist mix video and audio downloads.
   const [itemKinds, setItemKinds] = useState<Record<number, MediaKind>>({})
 
-  // Clipboard auto-detect: when the window gains focus and the clipboard holds a
+  // Clipboard auto-detect and links handed to AeroFetch from outside (the
-  // fresh link, offer it (without clobbering anything the user is already typing).
+  // aerofetch:// protocol or a "Send to" .url file) share one suggestion banner,
-  // The same banner also surfaces links handed to AeroFetch from outside — the
+  // driven by the same hook the library's add-source field uses. An external link
-  // aerofetch:// protocol or a "Send to" .url file (see onExternalUrl below).
+  // always takes priority over a clipboard guess — it's a direct request.
-  const [suggestion, setSuggestion] = useState<string | null>(null)
+  const {
-  const [suggestionSource, setSuggestionSource] = useState<'clipboard' | 'external'>('clipboard')
+    suggestion,
-  const urlRef = useRef('')
+    source: suggestionSource,
-  urlRef.current = url
+    accept: acceptLink,
-  const lastSeen = useRef<string | null>(null)
+    dismiss: dismissSuggestion,
-
+    offer: offerLink
-  useEffect(() => {
+  } = useClipboardLink(url)
-    let active = true
+  useEffect(() => window.api.onExternalUrl((incoming) => offerLink(incoming, 'external')), [offerLink])
-    async function check(): Promise<void> {
-      if (!useSettings.getState().clipboardWatch || urlRef.current.trim()) return
-      let text = ''
-      try {
-        text = (await window.api.readClipboard()) ?? ''
-      } catch {
-        return
-      }
-      if (!active) return
-      text = text.trim()
-      if (looksLikeUrl(text) && text !== lastSeen.current) {
-        setSuggestionSource('clipboard')
-        setSuggestion(text)
-      }
-    }
-    check()
-    window.addEventListener('focus', check)
-    return () => {
-      active = false
-      window.removeEventListener('focus', check)
-    }
-  }, [])
-
-  // A link handed in from outside always takes priority over whatever the
-  // clipboard banner was showing — it's a direct request, not a guess.
-  useEffect(
-    () =>
-      window.api.onExternalUrl((incomingUrl) => {
-        setSuggestionSource('external')
-        setSuggestion(incomingUrl)
-      }),
-    []
-  )
 
   function acceptSuggestion(): void {
-    if (!suggestion) return
+    const link = acceptLink()
-    lastSeen.current = suggestion
+    if (link) onUrlChange(link)
-    onUrlChange(suggestion)
-    setSuggestion(null)
-  }
-
-  function dismissSuggestion(): void {
-    lastSeen.current = suggestion
-    setSuggestion(null)
   }
 
   const usingFormats = kind === 'video' && info !== null && info.formats.length > 0

src/renderer/src/components/LibraryView.tsx

@@ -32,7 +32,7 @@ import {
 import type { MediaItem, Source } from '@shared/ipc'
 import { useSources } from '../store/sources'
 import { useSettings } from '../store/settings'
-import { useClipboardLink } from '../useClipboardLink'
+import { useClipboardLink, looksLikeSingleVideo } from '../useClipboardLink'
 import { useDownloads, type DownloadStatus } from '../store/downloads'
 import { thumbUrl } from '../thumb'
 import { MediaThumb } from './MediaThumb'
@@ -271,9 +271,9 @@ export function LibraryView(): React.JSX.Element {
 
   const [url, setUrl] = useState('')
   const [error, setError] = useState<string | null>(null)
-  // Offer a freshly-copied channel/playlist link, the same way the Downloads tab
+  // Offer a freshly-copied link the way the Downloads tab does, but skip single
-  // offers a copied video link.
+  // videos — a library source is a channel/playlist to sync, not a one-off.
-  const clip = useClipboardLink(url)
+  const clip = useClipboardLink(url, (u) => !looksLikeSingleVideo(u))
   const [selected, setSelected] = useState<Set<string>>(new Set())
   const [batchNote, setBatchNote] = useState<string | null>(null)
   const [syncNote, setSyncNote] = useState<string | null>(null)

src/renderer/src/components/SettingsView.tsx

@@ -968,7 +968,7 @@ export function SettingsView(): React.JSX.Element {
 
         <Field
           label="Update access token"
-          hint="Only needed if the release server requires sign-in (you'll see “could not reach the update server” without it). Paste a read-only Gitea token to enable update checks and downloads. Stored locally; leave blank for anonymous access."
+          hint="Only needed if the release server requires sign-in (you'll see “could not reach the update server” without it). Paste a read-only Gitea token to enable update checks and downloads. Stored encrypted on this device; leave blank for anonymous access."
         >
           <Input
             type="password"

src/renderer/src/useClipboardLink.ts

@@ -1,4 +1,4 @@
-import { useEffect, useRef, useState } from 'react'
+import { useCallback, useEffect, useRef, useState } from 'react'
 import { useSettings } from './store/settings'
 
 /** A quick heuristic for "this clipboard text is a link worth offering". */
@@ -13,13 +13,52 @@ export function looksLikeUrl(text: string): boolean {
   }
 }
 
+/**
+ * True for URLs that point at a single video rather than a channel/playlist. The
+ * library's add-source field wants collections to sync, not one-off videos, so it
+ * filters these out of its suggestions. Conservative on purpose: it only flags the
+ * common YouTube single-video shapes (a `/watch?v=` or `youtu.be/<id>` with no
+ * `list=` context), so a channel/playlist link — on YouTube or any other site — is
+ * never wrongly rejected. A `list=` param means "add the playlist", so it's kept.
+ */
+export function looksLikeSingleVideo(text: string): boolean {
+  let u: URL
+  try {
+    u = new URL(text.trim())
+  } catch {
+    return false
+  }
+  if (u.searchParams.has('list')) return false
+  const host = u.hostname.replace(/^www\./, '').toLowerCase()
+  if (host === 'youtube.com' || host === 'm.youtube.com' || host === 'music.youtube.com') {
+    return u.pathname === '/watch' && u.searchParams.has('v')
+  }
+  if (host === 'youtu.be') {
+    return /^\/[\w-]{6,}$/.test(u.pathname)
+  }
+  return false
+}
+
+/** Where an offered link came from — drives the banner's wording. */
+export type SuggestionSource = 'clipboard' | 'external'
+
 interface ClipboardLink {
-  /** the freshly-copied link being offered, or null */
+  /** the link currently being offered, or null */
   suggestion: string | null
+  /** where `suggestion` came from: a clipboard guess vs. a link handed in from outside */
+  source: SuggestionSource
   /** accept the suggestion: clears it and returns the link (or null if none) */
   accept: () => string | null
   /** dismiss the suggestion without using it */
   dismiss: () => void
+  /**
+   * Offer a link from outside the clipboard — e.g. the aerofetch:// protocol or a
+   * "Send to" .url file. Always takes priority over a clipboard guess and is shown
+   * even when clipboard-watch is off (it's a direct request, not a guess) and even
+   * while the field has text (the banner only fills the field once accepted).
+   * Stable identity, so it's safe to use as an effect dependency.
+   */
+  offer: (url: string, source?: SuggestionSource) => void
 }
 
 /**
@@ -28,14 +67,31 @@ interface ClipboardLink {
  * can auto-suggest a copied URL. Respects the `clipboardWatch` setting and never
  * interrupts text the user is already typing — pass the field's current value as
  * `currentValue` and the watcher stays quiet while it's non-empty.
+ *
+ * Pass `filter` to narrow what the clipboard offers — e.g. the library skips
+ * single-video links so it only suggests channels/playlists. It gates only the
+ * clipboard guess; links pushed via `offer()` bypass it (and the other guards),
+ * since they're explicit requests rather than guesses.
  */
-export function useClipboardLink(currentValue: string): ClipboardLink {
+export function useClipboardLink(
+  currentValue: string,
+  filter?: (url: string) => boolean
+): ClipboardLink {
   const [suggestion, setSuggestion] = useState<string | null>(null)
+  const [source, setSource] = useState<SuggestionSource>('clipboard')
   const valueRef = useRef('')
   valueRef.current = currentValue
+  // Held in a ref so an inline `filter` doesn't have to be memoized to keep the
+  // focus listener from re-subscribing every render.
+  const filterRef = useRef(filter)
+  filterRef.current = filter
   // The last link we offered or that the user dismissed — so re-focusing doesn't
   // keep re-offering the same one.
   const lastSeen = useRef<string | null>(null)
+  // Mirror the live suggestion so accept/dismiss can read it without depending on
+  // it — keeps their identity stable across renders.
+  const suggestionRef = useRef<string | null>(null)
+  suggestionRef.current = suggestion
 
   useEffect(() => {
     let active = true
@@ -49,7 +105,11 @@ export function useClipboardLink(currentValue: string): ClipboardLink {
       }
       if (!active) return
       text = text.trim()
-      if (looksLikeUrl(text) && text !== lastSeen.current) setSuggestion(text)
+      const wanted = looksLikeUrl(text) && (filterRef.current?.(text) ?? true)
+      if (wanted && text !== lastSeen.current) {
+        setSource('clipboard')
+        setSuggestion(text)
+      }
     }
     check()
     window.addEventListener('focus', check)
@@ -59,18 +119,23 @@ export function useClipboardLink(currentValue: string): ClipboardLink {
     }
   }, [])
 
-  return {
+  const accept = useCallback((): string | null => {
-    suggestion,
+    const link = suggestionRef.current
-    accept: () => {
+    if (!link) return null
-      if (!suggestion) return null
+    lastSeen.current = link
-      lastSeen.current = suggestion
-      const accepted = suggestion
     setSuggestion(null)
-      return accepted
+    return link
-    },
+  }, [])
-    dismiss: () => {
+
-      lastSeen.current = suggestion
+  const dismiss = useCallback((): void => {
+    lastSeen.current = suggestionRef.current
     setSuggestion(null)
-    }
+  }, [])
-  }
+
+  const offer = useCallback((url: string, src: SuggestionSource = 'external'): void => {
+    setSource(src)
+    setSuggestion(url)
+  }, [])
+
+  return { suggestion, source, accept, dismiss, offer }
 }

test/clipboardLink.test.ts

@@ -0,0 +1,75 @@
+import { describe, it, expect } from 'vitest'
+import { looksLikeUrl, looksLikeSingleVideo } from '../src/renderer/src/useClipboardLink'
+
+describe('looksLikeUrl', () => {
+  it('accepts http(s) URLs', () => {
+    expect(looksLikeUrl('https://youtube.com/watch?v=abc')).toBe(true)
+    expect(looksLikeUrl('http://example.com')).toBe(true)
+    expect(looksLikeUrl('https://example.com/a/b?c=d#frag')).toBe(true)
+  })
+
+  it('is scheme-case-insensitive', () => {
+    expect(looksLikeUrl('HTTPS://example.com')).toBe(true)
+    expect(looksLikeUrl('HtTp://example.com')).toBe(true)
+  })
+
+  it('trims surrounding whitespace', () => {
+    expect(looksLikeUrl('  https://example.com\n')).toBe(true)
+    expect(looksLikeUrl('\t http://example.com \t')).toBe(true)
+  })
+
+  it('rejects non-http(s) schemes', () => {
+    expect(looksLikeUrl('ftp://example.com')).toBe(false)
+    expect(looksLikeUrl('file:///c:/x')).toBe(false)
+    expect(looksLikeUrl('magnet:?xt=urn:btih:abc')).toBe(false)
+    expect(looksLikeUrl('javascript:alert(1)')).toBe(false)
+    expect(looksLikeUrl('mailto:a@b.com')).toBe(false)
+  })
+
+  it('rejects bare domains and scheme-less text', () => {
+    expect(looksLikeUrl('www.example.com')).toBe(false)
+    expect(looksLikeUrl('example.com/watch')).toBe(false)
+    expect(looksLikeUrl('see http://example.com')).toBe(false) // must start with the scheme
+  })
+
+  it('rejects empty, whitespace, and malformed input', () => {
+    expect(looksLikeUrl('')).toBe(false)
+    expect(looksLikeUrl('   ')).toBe(false)
+    expect(looksLikeUrl('not a link')).toBe(false)
+    expect(looksLikeUrl('http://')).toBe(false) // passes the prefix test but is not a valid URL
+  })
+})
+
+describe('looksLikeSingleVideo', () => {
+  it('flags YouTube single-video URLs', () => {
+    expect(looksLikeSingleVideo('https://www.youtube.com/watch?v=dQw4w9WgXcQ')).toBe(true)
+    expect(looksLikeSingleVideo('https://youtube.com/watch?v=abc123')).toBe(true)
+    expect(looksLikeSingleVideo('https://m.youtube.com/watch?v=abc123')).toBe(true)
+    expect(looksLikeSingleVideo('https://music.youtube.com/watch?v=abc123')).toBe(true)
+    expect(looksLikeSingleVideo('https://youtu.be/dQw4w9WgXcQ')).toBe(true)
+  })
+
+  it('keeps anything with a playlist context (?list=)', () => {
+    // A video opened in a playlist → the user likely wants the whole playlist.
+    expect(looksLikeSingleVideo('https://www.youtube.com/watch?v=abc&list=PL123')).toBe(false)
+    expect(looksLikeSingleVideo('https://youtu.be/abc?list=PL123')).toBe(false)
+  })
+
+  it('keeps channels and playlists', () => {
+    expect(looksLikeSingleVideo('https://www.youtube.com/@SomeChannel')).toBe(false)
+    expect(looksLikeSingleVideo('https://www.youtube.com/channel/UC123')).toBe(false)
+    expect(looksLikeSingleVideo('https://www.youtube.com/c/SomeChannel')).toBe(false)
+    expect(looksLikeSingleVideo('https://www.youtube.com/playlist?list=PL123')).toBe(false)
+  })
+
+  it('does not flag single videos on other sites (conservative)', () => {
+    // We can't reliably classify arbitrary hosts, so never reject them.
+    expect(looksLikeSingleVideo('https://vimeo.com/123456789')).toBe(false)
+    expect(looksLikeSingleVideo('https://example.com/watch?v=abc')).toBe(false)
+  })
+
+  it('returns false for non-URLs', () => {
+    expect(looksLikeSingleVideo('not a url')).toBe(false)
+    expect(looksLikeSingleVideo('')).toBe(false)
+  })
+})