diff --git a/models/Media.ts b/models/Media.ts
index 14d3b3c..a1f8890 100644
--- a/models/Media.ts
+++ b/models/Media.ts
@@ -13,7 +13,7 @@ export interface IMedia {
 const MediaSchema = new Schema<IMedia>({
     assetId: {
         type: String,
-        default: crypto.randomBytes(12).toString('hex')
+        default: () => crypto.randomBytes(12).toString('hex')
     },
     clientId: {
         type: Number,
diff --git a/models/ShortenedLink.ts b/models/ShortenedLink.ts
index e7c91b6..34cceee 100644
--- a/models/ShortenedLink.ts
+++ b/models/ShortenedLink.ts
@@ -12,7 +12,7 @@ export interface IShortenedLink {
 const ShortenedSchema = new Schema<IShortenedLink>({
     shortenedId: {
         type: String,
-        default: crypto.randomBytes(3).toString('hex')
+        default: () => crypto.randomBytes(3).toString('hex')
     },
     originalUrl: {
         type: String,