Finish preliminary backwards-compatible transition from user encryption scheme v1 to v2 with argon2 and protected key

backend/src/models/user.ts

@@ -1,11 +1,14 @@
 import { Schema, model, Types } from 'mongoose';
-import { MFA_METHOD_EMAIL } from '../variables';
 
 export interface IUser {
 	_id: Types.ObjectId;
 	email: string;
 	firstName?: string;
 	lastName?: string;
+	encryptionVersion: number;
+	protectedKey: string;
+	protectedKeyIV: string;
+	protectedKeyTag: string;
 	publicKey?: string;
 	encryptedPrivateKey?: string;
 	iv?: string;
@@ -28,6 +31,23 @@ const userSchema = new Schema<IUser>(
 		lastName: {
 			type: String
 		},
+		encryptionVersion: {
+			type: Number,
+			select: false,
+			default: 1 // to resolve backward-compatibility issues
+		},
+		protectedKey: { // introduced as part of encryption version 2
+			type: String,
+			select: false
+		},
+		protectedKeyIV: { // introduced as part of encryption version 2
+			type: String,
+			select: false
+		},
+		protectedKeyTag: { // introduced as part of encryption version 2
+			type: String,
+			select: false
+		},
 		publicKey: {
 			type: String,
 			select: false
@@ -36,11 +56,11 @@ const userSchema = new Schema<IUser>(
 			type: String,
 			select: false
 		},
-		iv: {
+		iv: { // iv of [encryptedPrivateKey]
 			type: String,
 			select: false
 		},
-		tag: {
+		tag: { // tag of [encryptedPrivateKey]
 			type: String,
 			select: false
 		},