added "DB dump" tool, WIP

dump-db/inc/data_key.js

@@ -0,0 +1,33 @@
+import crypto from "crypto";
+import sql from "./sql.js";
+
+function getDataKey(password) {
+    const passwordDerivedKey = getPasswordDerivedKey(password);
+
+    const encryptedDataKey = getOption('encryptedDataKey');
+
+    const decryptedDataKey = decrypt(passwordDerivedKey, encryptedDataKey, 16);
+
+    return decryptedDataKey;
+}
+
+function getPasswordDerivedKey(password) {
+    const salt = getOption('passwordDerivedKeySalt');
+
+    return getScryptHash(password, salt);
+}
+
+function getScryptHash(password, salt) {
+    const hashed = crypto.scryptSync(password, salt, 32,
+        {N: 16384, r:8, p:1});
+
+    return hashed;
+}
+
+function getOption(name) {
+    return sql.getValue("SELECT value FROM options WHERE name = ?", name);
+}
+
+module.exports = {
+    getDataKey
+};