changing from AES-256-CTR to AES-128-CBC for note encryption

migrations/0030__hello_world.js

@@ -0,0 +1 @@
+module.exports = async () => console.log("heeeelllooo!!!");

migrations/0031__change_encryption_to_CBC.js

@@ -0,0 +1,56 @@
+const sql = require('../services/sql');
+const data_encryption = require('../services/data_encryption');
+const password_encryption = require('../services/password_encryption');
+const my_scrypt = require('../services/my_scrypt');
+const readline = require('readline');
+
+const cl = readline.createInterface(process.stdin, process.stdout);
+
+function question(q) {
+    return new Promise( (res, rej) => {
+        cl.question( q, answer => {
+            res(answer);
+        })
+    });
+}
+
+module.exports = async () => {
+    const password = await question("Enter password: ");
+    const dataKey = await password_encryption.getDecryptedDataKey(password);
+
+    const protectedNotes = await sql.getResults("SELECT * FROM notes WHERE is_protected = 1");
+
+    for (const note of protectedNotes) {
+        console.log("Encrypted: ", note.note_title);
+
+        const decryptedTitle = data_encryption.decrypt(dataKey, note.note_title);
+
+        console.log("Decrypted title: ", decryptedTitle);
+
+        note.note_title = data_encryption.encryptCbc(dataKey, "0" + note.note_id, decryptedTitle);
+
+        const decryptedText = data_encryption.decrypt(dataKey, note.note_text);
+        note.note_text = data_encryption.encryptCbc(dataKey, "1" + note.note_id, decryptedText);
+
+        await sql.execute("UPDATE notes SET note_title = ?, note_text = ? WHERE note_id = ?", [note.note_title, note.note_text, note.note_id]);
+    }
+
+    const protectedNotesHistory = await sql.getResults("SELECT * FROM notes_history WHERE is_protected = 1");
+
+    for (const noteHistory of protectedNotesHistory) {
+        const decryptedTitle = data_encryption.decrypt(dataKey, noteHistory.note_title);
+        noteHistory.note_title = data_encryption.encryptCbc(dataKey, "0" + noteHistory.note_history_id, decryptedTitle);
+
+        const decryptedText = data_encryption.decrypt(dataKey, noteHistory.note_text);
+        noteHistory.note_text = data_encryption.encryptCbc(dataKey, "1" + noteHistory.note_history_id, decryptedText);
+
+        await sql.execute("UPDATE notes SET note_title = ?, note_text = ? WHERE note_id = ?", [noteHistory.note_title, noteHistory.note_text, noteHistory.note_history_id]);
+    }
+
+    const passwordDerivedKey = await my_scrypt.getPasswordDerivedKey(password);
+
+    // trimming to 128bits (for AES-128)
+    const trimmedDataKey = dataKey.slice(0, 16);
+
+    await password_encryption.encryptDataKey(passwordDerivedKey, trimmedDataKey);
+};

package.json

@@ -6,7 +6,7 @@
   "scripts": {
     "start": "node ./bin/www",
     "test-electron": "xo",
-	"rebuild-electron": "electron-rebuild",
+    "rebuild-electron": "electron-rebuild",
     "start-electron": "electron .",
     "build-electron": "electron-packager . --out=dist --asar --overwrite --all",
     "start-forge": "electron-forge start",
@@ -40,6 +40,7 @@
     "electron-packager": "^8.0.0",
     "electron-prebuilt-compile": "1.8.2-beta.2",
     "electron-rebuild": "^1.6.0",
+    "tape": "^4.8.0",
     "xo": "^0.18.0"
   },
   "config": {

routes/api/note_history.js

@@ -15,8 +15,8 @@ router.get('/:noteId', auth.checkApiAuth, async (req, res, next) => {
 
     for (const hist of history) {
         if (hist.is_protected) {
-            hist.note_title = data_encryption.decrypt(dataKey, hist.note_title);
-            hist.note_text = data_encryption.decrypt(dataKey, hist.note_text);
+            hist.note_title = data_encryption.decryptCbc(dataKey, data_encryption.noteTitleIv(hist.note_history_id), hist.note_title);
+            hist.note_text = data_encryption.decryptCbc(dataKey, data_encryption.noteTitleIv(hist.note_history_id), hist.note_text);
         }
     }
 

routes/api/notes.js

@@ -21,8 +21,8 @@ router.get('/:noteId', auth.checkApiAuth, async (req, res, next) => {
     if (detail.is_protected) {
         const dataKey = protected_session.getDataKey(req);
 
-        detail.note_title = data_encryption.decrypt(dataKey, detail.note_title);
-        detail.note_text = data_encryption.decrypt(dataKey, detail.note_text);
+        detail.note_title = data_encryption.decryptCbc(dataKey, data_encryption.noteTitleIv(noteId), detail.note_title);
+        detail.note_text = data_encryption.decryptCbc(dataKey, data_encryption.noteTextIv(noteId), detail.note_text);
     }
 
     res.send({

routes/api/tree.js

@@ -28,7 +28,7 @@ router.get('/', auth.checkApiAuth, async (req, res, next) => {
 
     for (const note of notes) {
         if (note.is_protected) {
-            note.note_title = data_encryption.decrypt(dataKey, note.note_title);
+            note.note_title = data_encryption.decryptCbc(dataKey, data_encryption.noteTitleIv(note.note_id), note.note_title);
         }
 
         note.children = [];

services/data_encryption.js

@@ -12,6 +12,15 @@ function getDataAes(dataKey) {
     return new aesjs.ModeOfOperation.ctr(dataKey, new aesjs.Counter(5));
 }
 
+function arraysIdentical(a, b) {
+    let i = a.length;
+    if (i !== b.length) return false;
+    while (i--) {
+        if (a[i] !== b[i]) return false;
+    }
+    return true;
+}
+
 function decrypt(dataKey, encryptedBase64) {
     if (!dataKey) {
         return "[protected]";
@@ -54,21 +63,78 @@ function encrypt(dataKey, plainText) {
     return utils.toBase64(encryptedBytes);
 }
 
+function shaArray(content) {
+    // we use this as simple checksum and don't rely on its security so SHA-1 is good enough
+    return crypto.createHash('sha1').update(content).digest('base64');
+}
+
 function sha256Array(content) {
     return crypto.createHash('sha256').update(content).digest();
 }
 
-function arraysIdentical(a, b) {
-    let i = a.length;
-    if (i !== b.length) return false;
-    while (i--) {
-        if (a[i] !== b[i]) return false;
+function pad(data) {
+    let padded = Array.from(data);
+
+    if (data.length >= 16) {
+        padded = padded.slice(0, 16);
     }
-    return true;
+    else {
+        padded = padded.concat(Array(16 - padded.length).fill(0));
+    }
+
+    return Buffer.from(padded);
+}
+
+function encryptCbc(dataKey, iv, plainText) {
+    if (!dataKey) {
+        throw new Error("No data key!");
+    }
+
+    const cipher = crypto.createCipheriv('aes-128-cbc', pad(dataKey), pad(iv));
+
+    const digest = shaArray(plainText).slice(0, 4);
+
+    const digestWithPayload = digest + plainText;
+
+    const encryptedData = cipher.update(digestWithPayload, 'utf8', 'base64') + cipher.final('base64');
+
+    return encryptedData;
+}
+
+function decryptCbc(dataKey, iv, cipherText) {
+    if (!dataKey) {
+        return "[protected]";
+    }
+
+    const decipher = crypto.createDecipheriv('aes-128-cbc', pad(dataKey), pad(iv));
+    const decryptedBytes  = decipher.update(cipherText, 'base64', 'utf-8') + decipher.final('utf-8');
+
+    const digest = decryptedBytes.slice(0, 4);
+    const payload = decryptedBytes.slice(4);
+
+    const computedDigest = shaArray(payload).slice(0, 4);
+
+    if (!arraysIdentical(digest, computedDigest)) {
+        return false;
+    }
+
+    return payload;
+}
+
+function noteTitleIv(iv) {
+    return "0" + iv;
+}
+
+function noteTextIv(iv) {
+    return "1" + iv;
 }
 
 module.exports = {
     getProtectedSessionId,
     decrypt,
-    encrypt
+    encrypt,
+    encryptCbc,
+    decryptCbc,
+    noteTitleIv,
+    noteTextIv
 };

services/migration.js

@@ -4,8 +4,8 @@ const options = require('./options');
 const fs = require('fs-extra');
 const log = require('./log');
 
-const APP_DB_VERSION = 29;
-const MIGRATIONS_DIR = "./migrations";
+const APP_DB_VERSION = 31;
+const MIGRATIONS_DIR = "migrations";
 
 async function migrate() {
     const migrations = [];
@@ -16,18 +16,20 @@ async function migrate() {
     const currentDbVersion = parseInt(await options.getOption('db_version'));
 
     fs.readdirSync(MIGRATIONS_DIR).forEach(file => {
-        const match = file.match(/([0-9]{4})__([a-zA-Z0-9_ ]+)\.sql/);
+        const match = file.match(/([0-9]{4})__([a-zA-Z0-9_ ]+)\.(sql|js)/);
 
         if (match) {
             const dbVersion = parseInt(match[1]);
 
             if (dbVersion > currentDbVersion) {
                 const name = match[2];
+                const type = match[3];
 
                 const migrationRecord = {
                     dbVersion: dbVersion,
                     name: name,
-                    file: file
+                    file: file,
+                    type: type
                 };
 
                 migrations.push(migrationRecord);
@@ -38,13 +40,26 @@ async function migrate() {
     migrations.sort((a, b) => a.dbVersion - b.dbVersion);
 
     for (const mig of migrations) {
-        const migrationSql = fs.readFileSync(MIGRATIONS_DIR + "/" + mig.file).toString('utf8');
-
         try {
-            log.info("Attempting migration to version " + mig.dbVersion + " with script: " + migrationSql);
+            log.info("Attempting migration to version " + mig.dbVersion);
 
             await sql.doInTransaction(async () => {
-                await sql.executeScript(migrationSql);
+                if (mig.type === 'sql') {
+                    const migrationSql = fs.readFileSync(MIGRATIONS_DIR + "/" + mig.file).toString('utf8');
+
+                    console.log("Migration with SQL script: " + migrationSql);
+
+                    await sql.executeScript(migrationSql);
+                }
+                else if (mig.type === 'js') {
+                    console.log("Migration with JS module");
+
+                    const migrationModule = require("../" + MIGRATIONS_DIR + "/" + mig.file);
+                    await migrationModule();
+                }
+                else {
+                    throw new Error("Unknown migration type " + mig.type);
+                }
 
                 await options.setOption("db_version", mig.dbVersion);
             });

services/notes.js

@@ -65,8 +65,8 @@ async function createNewNote(parentNoteId, note, browserId) {
 }
 
 async function encryptNote(note, ctx) {
-    note.detail.note_title = data_encryption.encrypt(ctx.getDataKey(), note.detail.note_title);
-    note.detail.note_text = data_encryption.encrypt(ctx.getDataKey(), note.detail.note_text);
+    note.detail.note_title = data_encryption.encryptCbc(ctx.getDataKey(), data_encryption.noteTitleIv(note.detail.note_id), note.detail.note_title);
+    note.detail.note_text = data_encryption.encryptCbc(ctx.getDataKey(), data_encryption.noteTextIv(note.detail.note_id), note.detail.note_text);
 }
 
 async function protectNoteRecursively(noteId, dataKey, protect) {
@@ -85,15 +85,15 @@ async function protectNote(note, dataKey, protect) {
     let changed = false;
 
     if (protect && !note.is_protected) {
-        note.note_title = data_encryption.encrypt(dataKey, note.note_title);
-        note.note_text = data_encryption.encrypt(dataKey, note.note_text);
+        note.note_title = data_encryption.encryptCbc(dataKey, data_encryption.noteTitleIv(note.note_id), note.note_title);
+        note.note_text = data_encryption.encryptCbc(dataKey, data_encryption.noteTextIv(note.note_id), note.note_text);
         note.is_protected = true;
 
         changed = true;
     }
     else if (!protect && note.is_protected) {
-        note.note_title = data_encryption.decrypt(dataKey, note.note_title);
-        note.note_text = data_encryption.decrypt(dataKey, note.note_text);
+        note.note_title = data_encryption.decryptCbc(dataKey, data_encryption.noteTitleIv(note.note_id), note.note_title);
+        note.note_text = data_encryption.decryptCbc(dataKey, data_encryption.noteTextIv(note.note_id), note.note_text);
         note.is_protected = false;
 
         changed = true;
@@ -116,13 +116,13 @@ async function protectNoteHistory(noteId, dataKey, protect) {
 
     for (const history of historyToChange) {
         if (protect) {
-            history.note_title = data_encryption.encrypt(dataKey, history.note_title);
-            history.note_text = data_encryption.encrypt(dataKey, history.note_text);
+            history.note_title = data_encryption.encryptCbc(dataKey, data_encryption.noteTitleIv(history.note_history_id), history.note_title);
+            history.note_text = data_encryption.encryptCbc(dataKey, data_encryption.noteTextIv(history.note_history_id), history.note_text);
             history.is_protected = true;
         }
         else {
-            history.note_title = data_encryption.decrypt(dataKey, history.note_title);
-            history.note_text = data_encryption.decrypt(dataKey, history.note_text);
+            history.note_title = data_encryption.decryptCbc(dataKey, data_encryption.noteTitleIv(history.note_history_id), history.note_title);
+            history.note_text = data_encryption.decryptCbc(dataKey, data_encryption.noteTextIv(history.note_history_id), history.note_text);
             history.is_protected = false;
         }
 

test/cbc_encryption.js

@@ -0,0 +1,14 @@
+const test = require('tape');
+const data_encryption = require('../services/data_encryption');
+
+test('encrypt & decrypt', t => {
+    const dataKey = [1,2,3];
+    const iv = [4,5,6];
+    const plainText = "Hello World!";
+
+    const cipherText = data_encryption.encryptCbc(dataKey, iv, plainText);
+    const decodedPlainText = data_encryption.decryptCbc(dataKey, iv, cipherText);
+
+    t.equal(decodedPlainText, plainText);
+    t.end();
+});