feat: [closes #86] Encrypted file transfers (#87)

* feat: [#86] encrypt torrent data before upload
* feat: [#86] decrypt torrent data after download
* feat: [#86] use room ID as encryption key
* feat: [#86] show alerts for encryption activity
* feat: [#86] show progress indicator while encrypting files

package-lock.json

@@ -36,6 +36,8 @@
         "react-router-dom": "^6.3.0",
         "react-scripts": "5.0.1",
         "react-syntax-highlighter": "^15.5.0",
+        "readable-stream-node-to-web": "^1.0.1",
+        "readable-web-to-node-stream": "^3.0.2",
         "remark-gfm": "^3.0.1",
         "sass": "^1.54.3",
         "streamsaver": "^2.0.6",
@@ -45,7 +47,8 @@
         "typescript": "^4.7.4",
         "uuid": "^8.3.2",
         "web-vitals": "^2.1.4",
-        "webtorrent": "^1.9.4"
+        "webtorrent": "^1.9.4",
+        "wormhole-crypto": "^0.3.1"
       },
       "devDependencies": {
         "@types/react-syntax-highlighter": "^15.5.5",
@@ -22489,6 +22492,26 @@
         "node": ">= 6"
       }
     },
+    "node_modules/readable-stream-node-to-web": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/readable-stream-node-to-web/-/readable-stream-node-to-web-1.0.1.tgz",
+      "integrity": "sha512-OGzi2VKLa8H259kAx7BIwuRrXHGcxeHj4RdASSgEGBP9Q2wowdPvBc65upF4Q9O05qWgKqBw1+9PiLTtObl7uQ=="
+    },
+    "node_modules/readable-web-to-node-stream": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/readable-web-to-node-stream/-/readable-web-to-node-stream-3.0.2.tgz",
+      "integrity": "sha512-ePeK6cc1EcKLEhJFt/AebMCLL+GgSKhuygrZ/GLaKZYEecIgIECf4UaUuaByiGtzckwR4ain9VzUh95T1exYGw==",
+      "dependencies": {
+        "readable-stream": "^3.6.0"
+      },
+      "engines": {
+        "node": ">=8"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/Borewit"
+      }
+    },
     "node_modules/readdirp": {
       "version": "3.6.0",
       "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-3.6.0.tgz",
@@ -26674,6 +26697,14 @@
         "workbox-core": "6.5.4"
       }
     },
+    "node_modules/wormhole-crypto": {
+      "version": "0.3.1",
+      "resolved": "https://registry.npmjs.org/wormhole-crypto/-/wormhole-crypto-0.3.1.tgz",
+      "integrity": "sha512-P6dsua8VTTbaLozTSbeDWBuXcoAJABH8a+XutfMg9Vb2a/roUPLFvkgtuJcXorp8hwLM5RguQEWtMZqgpJYohA==",
+      "dependencies": {
+        "base64-js": "^1.5.1"
+      }
+    },
     "node_modules/wrap-ansi": {
       "version": "7.0.0",
       "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-7.0.0.tgz",
@@ -43199,6 +43230,19 @@
         "util-deprecate": "^1.0.1"
       }
     },
+    "readable-stream-node-to-web": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/readable-stream-node-to-web/-/readable-stream-node-to-web-1.0.1.tgz",
+      "integrity": "sha512-OGzi2VKLa8H259kAx7BIwuRrXHGcxeHj4RdASSgEGBP9Q2wowdPvBc65upF4Q9O05qWgKqBw1+9PiLTtObl7uQ=="
+    },
+    "readable-web-to-node-stream": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/readable-web-to-node-stream/-/readable-web-to-node-stream-3.0.2.tgz",
+      "integrity": "sha512-ePeK6cc1EcKLEhJFt/AebMCLL+GgSKhuygrZ/GLaKZYEecIgIECf4UaUuaByiGtzckwR4ain9VzUh95T1exYGw==",
+      "requires": {
+        "readable-stream": "^3.6.0"
+      }
+    },
     "readdirp": {
       "version": "3.6.0",
       "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-3.6.0.tgz",
@@ -46280,6 +46324,14 @@
         "workbox-core": "6.5.4"
       }
     },
+    "wormhole-crypto": {
+      "version": "0.3.1",
+      "resolved": "https://registry.npmjs.org/wormhole-crypto/-/wormhole-crypto-0.3.1.tgz",
+      "integrity": "sha512-P6dsua8VTTbaLozTSbeDWBuXcoAJABH8a+XutfMg9Vb2a/roUPLFvkgtuJcXorp8hwLM5RguQEWtMZqgpJYohA==",
+      "requires": {
+        "base64-js": "^1.5.1"
+      }
+    },
     "wrap-ansi": {
       "version": "7.0.0",
       "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-7.0.0.tgz",

package.json

@@ -32,6 +32,8 @@
     "react-router-dom": "^6.3.0",
     "react-scripts": "5.0.1",
     "react-syntax-highlighter": "^15.5.0",
+    "readable-stream-node-to-web": "^1.0.1",
+    "readable-web-to-node-stream": "^3.0.2",
     "remark-gfm": "^3.0.1",
     "sass": "^1.54.3",
     "streamsaver": "^2.0.6",
@@ -41,7 +43,8 @@
     "typescript": "^4.7.4",
     "uuid": "^8.3.2",
     "web-vitals": "^2.1.4",
-    "webtorrent": "^1.9.4"
+    "webtorrent": "^1.9.4",
+    "wormhole-crypto": "^0.3.1"
   },
   "scripts": {
     "start": "react-scripts start",

src/components/Message/InlineMedia.tsx

@@ -1,8 +1,11 @@
-import { useEffect, useRef, useState } from 'react'
+import { useContext, useEffect, useRef, useState } from 'react'
+import { TorrentFile } from 'webtorrent'
+import { ReadableWebToNodeStream } from 'readable-web-to-node-stream'
 import CircularProgress from '@mui/material/CircularProgress'
+import { Typography } from '@mui/material'
 
 import { fileTransfer } from 'services/FileTransfer'
-import { Typography } from '@mui/material'
+import { ShellContext } from 'contexts/ShellContext'
 
 type TorrentFiles = Awaited<ReturnType<typeof fileTransfer.download>>
 
@@ -17,18 +20,43 @@ interface InlineFileProps {
 export const InlineFile = ({ file }: InlineFileProps) => {
   const containerRef = useRef(null)
   const [didRenderingMediaFail, setDidRenderingMediaFail] = useState(false)
+  const shellContext = useContext(ShellContext)
 
   useEffect(() => {
+    ;(async () => {
       const { current: container } = containerRef
 
       if (!container) return
 
       try {
-      file.appendTo(container)
+        if (typeof shellContext.roomId !== 'string') {
+          throw new Error('shellContext.roomId is not a string')
+        }
+
+        const readStream: NodeJS.ReadableStream = new ReadableWebToNodeStream(
+          await fileTransfer.getDecryptedFileReadStream(
+            file,
+            shellContext.roomId
+          )
+          // ReadableWebToNodeStream is the same as NodeJS.ReadableStream. The
+          // library's typing is wrong.
+        ) as any
+
+        const decryptedFile: TorrentFile = {
+          ...file,
+          createReadStream: () => {
+            return readStream
+          },
+        }
+
+        Object.setPrototypeOf(decryptedFile, Object.getPrototypeOf(file))
+        decryptedFile.appendTo(container)
       } catch (e) {
+        console.error(e)
         setDidRenderingMediaFail(true)
       }
-  }, [file, containerRef])
+    })()
+  }, [file, containerRef, shellContext.roomId])
 
   return (
     <div ref={containerRef}>
@@ -44,16 +72,20 @@ export const InlineFile = ({ file }: InlineFileProps) => {
 export const InlineMedia = ({ magnetURI }: InlineMediaProps) => {
   const [hasDownloadInitiated, setHasDownloadInitiated] = useState(false)
   const [downloadedFiles, setDownloadedFiles] = useState<TorrentFiles>([])
+  const shellContext = useContext(ShellContext)
 
   useEffect(() => {
     ;(async () => {
       if (hasDownloadInitiated) return
+      if (typeof shellContext.roomId !== 'string') {
+        throw new Error('shellContext.roomId is not a string')
+      }
 
       setHasDownloadInitiated(true)
-      const files = await fileTransfer.download(magnetURI)
+      const files = await fileTransfer.download(magnetURI, shellContext.roomId)
       setDownloadedFiles(files)
     })()
-  }, [hasDownloadInitiated, magnetURI])
+  }, [hasDownloadInitiated, magnetURI, shellContext.roomId])
 
   return (
     <>

src/components/Room/RoomFileUploadControls.tsx

@@ -4,6 +4,7 @@ import UploadFile from '@mui/icons-material/UploadFile'
 import Cancel from '@mui/icons-material/Cancel'
 import Fab from '@mui/material/Fab'
 import Tooltip from '@mui/material/Tooltip'
+import CircularProgress from '@mui/material/CircularProgress'
 
 import { RoomContext } from 'contexts/RoomContext'
 import { PeerRoom } from 'services/PeerRoom/PeerRoom'
@@ -60,6 +61,8 @@ export function RoomFileUploadControls({
 
   const disableFileUpload = !isFileSharingEnabled || isMessageSending
 
+  const buttonIcon = isSharingFile ? <Cancel /> : <UploadFile />
+
   return (
     <Box
       sx={{
@@ -91,7 +94,11 @@ export function RoomFileUploadControls({
           onClick={handleToggleScreenShareButtonClick}
           disabled={disableFileUpload}
         >
-          {isSharingFile ? <Cancel /> : <UploadFile />}
+          {isFileSharingEnabled ? (
+            buttonIcon
+          ) : (
+            <CircularProgress variant="indeterminate" color="inherit" />
+          )}
         </Fab>
       </Tooltip>
     </Box>

src/components/Room/useRoom.ts

@@ -322,7 +322,7 @@ export function useRoom(
   if (!showVideoDisplay && !isShowingMessages) setIsShowingMessages(true)
 
   const handleInlineMediaUpload = async (files: File[]) => {
-    const fileOfferId = await fileTransfer.offer(files)
+    const fileOfferId = await fileTransfer.offer(files, roomId)
 
     const unsentInlineMedia: UnsentInlineMedia = {
       authorId: userId,

src/components/Room/useRoomFileShare.ts

@@ -32,7 +32,7 @@ export function useRoomFileShare({
   >(null)
   const [isFileSharingEnabled, setIsFileSharingEnabled] = useState(true)
 
-  const { peerList, setPeerList } = shellContext
+  const { peerList, setPeerList, showAlert } = shellContext
   const { peerOfferedFileMetadata, setPeerOfferedFileMetadata } = roomContext
 
   const [sendFileOfferMetadata, receiveFileOfferMetadata] =
@@ -121,7 +121,19 @@ export function useRoomFileShare({
     setSharedFiles(files)
     setIsFileSharingEnabled(false)
 
-    const magnetURI = await fileTransfer.offer(files)
+    if (typeof shellContext.roomId !== 'string') {
+      throw new Error('shellContext.roomId is not a string')
+    }
+
+    const alertText =
+      files.length > 1
+        ? 'Encrypting a copy of the files...'
+        : 'Encrypting a copy of the file...'
+    showAlert(alertText, { severity: 'info' })
+
+    const magnetURI = await fileTransfer.offer(files, shellContext.roomId)
+
+    showAlert('Encryption complete', { severity: 'success' })
 
     if (inlineMediaFiles.length > 0) {
       onInlineMediaUpload(inlineMediaFiles)

src/components/Shell/PeerDownloadFileButton.tsx

@@ -38,7 +38,14 @@ export const PeerDownloadFileButton = ({
     setDownloadProgress(null)
 
     try {
-      await fileTransfer.download(offeredFileId, { doSave: true, onProgress })
+      if (typeof shellContext.roomId !== 'string') {
+        throw new Error('shellContext.roomId is not a string')
+      }
+
+      await fileTransfer.download(offeredFileId, shellContext.roomId, {
+        doSave: true,
+        onProgress,
+      })
     } catch (e) {
       if (isError(e)) {
         shellContext.showAlert(e.message, {

src/services/FileTransfer/FileTransfer.ts

@@ -1,14 +1,36 @@
-import WebTorrent, { Torrent } from 'webtorrent'
+import WebTorrent, { Torrent, TorrentFile } from 'webtorrent'
 import streamSaver from 'streamsaver'
 // @ts-ignore
+import { Keychain, plaintextSize } from 'wormhole-crypto'
+// @ts-ignore
 import idbChunkStore from 'idb-chunk-store'
 import { detectIncognito } from 'detectincognitojs'
 
 import { trackerUrls } from 'config/trackerUrls'
 import { streamSaverUrl } from 'config/streamSaverUrl'
 
+import { ReadableWebToNodeStream } from 'readable-web-to-node-stream'
+// @ts-ignore
+import nodeToWebStream from 'readable-stream-node-to-web'
+
 streamSaver.mitm = streamSaverUrl
 
+interface NamedReadableWebToNodeStream extends NodeJS.ReadableStream {
+  name?: string
+}
+
+const getKeychain = (password: string) => {
+  const encoder = new TextEncoder()
+  const keyLength = 16
+  const padding = new Array(keyLength).join('0')
+  const key = password.concat(padding).slice(0, keyLength)
+  const salt = window.location.origin.concat(padding).slice(0, keyLength)
+
+  const keychain = new Keychain(encoder.encode(key), encoder.encode(salt))
+
+  return keychain
+}
+
 interface DownloadOpts {
   doSave?: boolean
   onProgress?: (progress: number) => void
@@ -19,51 +41,18 @@ export class FileTransfer {
 
   private torrents: Record<Torrent['magnetURI'], Torrent> = {}
 
-  private async saveTorrentFiles(torrent: Torrent) {
+  private async saveTorrentFiles(torrent: Torrent, password: string) {
     for (const file of torrent.files) {
       try {
-        await new Promise<void>((resolve, reject) => {
+        const readStream = await this.getDecryptedFileReadStream(file, password)
-          const fileStream = streamSaver.createWriteStream(file.name, {
+
-            size: file.length,
+        const writeStream = streamSaver.createWriteStream(file.name, {
+          size: plaintextSize(file.length),
         })
 
-          const writeStream = fileStream.getWriter()
+        await readStream.pipeTo(writeStream)
-          const readStream = file.createReadStream()
-          let aborted = false
-
-          const handleData = async (data: ArrayBuffer) => {
-            try {
-              await writeStream.write(data)
-            } catch (e) {
-              writeStream.abort()
-              readStream.off('data', handleData)
-              aborted = true
-              reject()
-            }
-          }
-
-          const handleBeforePageUnloadForFile = () => {
-            // Clean up any broken downloads
-            writeStream.abort()
-          }
-
-          window.addEventListener('beforeunload', handleBeforePageUnloadForFile)
-
-          const handleEnd = async () => {
-            window.removeEventListener(
-              'beforeunload',
-              handleBeforePageUnloadForFile
-            )
-
-            if (aborted) return
-
-            await writeStream.close()
-            resolve()
-          }
-
-          readStream.on('data', handleData).on('end', handleEnd)
-        })
       } catch (e) {
+        console.error(e)
         throw new Error('Download aborted')
       }
     }
@@ -73,7 +62,20 @@ export class FileTransfer {
     window.addEventListener('beforeunload', this.handleBeforePageUnload)
   }
 
-  async download(magnetURI: string, { onProgress, doSave }: DownloadOpts = {}) {
+  async getDecryptedFileReadStream(file: TorrentFile, password: string) {
+    const keychain = getKeychain(password)
+    const readStream: ReadableStream = await keychain.decryptStream(
+      nodeToWebStream(file.createReadStream())
+    )
+
+    return readStream
+  }
+
+  async download(
+    magnetURI: string,
+    password: string,
+    { onProgress, doSave }: DownloadOpts = {}
+  ) {
     let torrent = this.torrents[magnetURI]
 
     if (!torrent) {
@@ -107,7 +109,7 @@ export class FileTransfer {
 
     if (doSave) {
       try {
-        await this.saveTorrentFiles(torrent)
+        await this.saveTorrentFiles(torrent, password)
       } catch (e) {
         torrent.off('download', handleDownload)
 
@@ -119,12 +121,35 @@ export class FileTransfer {
     return torrent.files
   }
 
-  async offer(files: Parameters<typeof this.webTorrentClient.seed>[0]) {
+  async offer(files: File[] | FileList, password: string) {
     const { isPrivate } = await detectIncognito()
 
+    const filesToSeed: File[] =
+      files instanceof FileList ? Array.from(files) : files
+
+    const encryptedFiles = await Promise.all(
+      filesToSeed.map(async file => {
+        const encryptedStream = await getKeychain(password).encryptStream(
+          file.stream()
+        )
+
+        // WebTorrent only accepts Node-style ReadableStreams
+        const nodeStream: NamedReadableWebToNodeStream =
+          new ReadableWebToNodeStream(
+            encryptedStream
+            // ReadableWebToNodeStream is the same as NodeJS.ReadableStream.
+            // The library's typing is wrong.
+          ) as any as NodeJS.ReadableStream
+
+        nodeStream.name = file.name
+
+        return nodeStream
+      })
+    )
+
     const torrent = await new Promise<Torrent>(res => {
       this.webTorrentClient.seed(
-        files,
+        encryptedFiles,
         {
           announce: trackerUrls,
           // If the user is using their browser's private mode, IndexedDB will

src/setupTests.ts

@@ -12,3 +12,8 @@ jest.mock('webtorrent', () => ({
   __esModule: true,
   default: class WebTorrent {},
 }))
+
+jest.mock('wormhole-crypto', () => ({
+  __esModule: true,
+  Keychain: class Keychain {},
+}))