moved all sources to src directory

src/services/data_encryption.js

@@ -0,0 +1,101 @@
+"use strict";
+
+const crypto = require('crypto');
+const log = require('./log');
+
+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 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();
+}
+
+function pad(data) {
+    let padded = Array.from(data);
+
+    if (data.length >= 16) {
+        padded = padded.slice(0, 16);
+    }
+    else {
+        padded = padded.concat(Array(16 - padded.length).fill(0));
+    }
+
+    return Buffer.from(padded);
+}
+
+function encrypt(key, iv, plainText) {
+    if (!key) {
+        throw new Error("No data key!");
+    }
+
+    const plainTextBuffer = Buffer.from(plainText);
+
+    const cipher = crypto.createCipheriv('aes-128-cbc', pad(key), pad(iv));
+
+    const digest = shaArray(plainTextBuffer).slice(0, 4);
+
+    const digestWithPayload = Buffer.concat([digest, plainTextBuffer]);
+
+    const encryptedData = Buffer.concat([cipher.update(digestWithPayload), cipher.final()]);
+
+    return encryptedData.toString('base64');
+}
+
+function decrypt(key, iv, cipherText) {
+    if (!key) {
+        return "[protected]";
+    }
+
+    const decipher = crypto.createDecipheriv('aes-128-cbc', pad(key), pad(iv));
+
+    const cipherTextBuffer = Buffer.from(cipherText, 'base64');
+    const decryptedBytes = Buffer.concat([decipher.update(cipherTextBuffer), decipher.final()]);
+
+    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 decryptString(dataKey, iv, cipherText) {
+    const buffer = decrypt(dataKey, iv, cipherText);
+
+    const str = buffer.toString('utf-8');
+
+    if (str === 'false') {
+        log.error("Could not decrypt string. Buffer: " + buffer);
+
+        throw new Error("Could not decrypt string.");
+    }
+
+    return str;
+}
+
+function noteTitleIv(iv) {
+    return "0" + iv;
+}
+
+function noteTextIv(iv) {
+    return "1" + iv;
+}
+
+module.exports = {
+    encrypt,
+    decrypt,
+    decryptString,
+    noteTitleIv,
+    noteTextIv
+};