Begin refactoring backfilling and preparation operations into setup and start adding encryption metadata to models

backend/src/models/backupPrivateKey.ts

@@ -1,4 +1,9 @@
 import { Schema, model, Types } from 'mongoose';
+import { 
+	ALGORITHM_AES_256_GCM,
+	ENCODING_SCHEME_UTF8,
+	ENCODING_SCHEME_BASE64
+} from '../variables';
 
 export interface IBackupPrivateKey {
 	_id: Types.ObjectId;
@@ -7,6 +12,9 @@ export interface IBackupPrivateKey {
 	iv: string;
 	tag: string;
 	salt: string;
+	algorithm: string;
+	keySize: number;
+	keyEncoding: 'base64' | 'utf8';
 	verifier: string;
 }
 
@@ -32,6 +40,24 @@ const backupPrivateKeySchema = new Schema<IBackupPrivateKey>(
 			select: false,
 			required: true
 		},
+        algorithm: { // the encryption algorithm used
+            type: String,
+            enum: [ALGORITHM_AES_256_GCM],
+            required: true
+        },
+        keySize: { // the size of the key used in the algorithm
+            type: Number,
+            enum: [256],
+            required: true
+        },
+        keyEncoding: {
+            type: String,
+            enum: [
+                ENCODING_SCHEME_UTF8,
+                ENCODING_SCHEME_BASE64
+            ],
+			required: true
+        },
 		salt: {
 			type: String,
 			select: false,