diff --git a/packages/core/src/utils/crypto.ts b/packages/core/src/utils/crypto.ts
index b02b00f1..507ac5f3 100644
--- a/packages/core/src/utils/crypto.ts
+++ b/packages/core/src/utils/crypto.ts
@@ -114,6 +114,9 @@ export function decryptString(data: string, secretKey?: Buffer): Response {
     secretKey = Buffer.from(Env.SECRET_KEY, 'hex');
   }
   try {
+    if (!isEncrypted(data)) {
+      throw new Error('The data was not in an expected encrypted format');
+    }
     const [_, ivHex, encryptedHex] = decodeURIComponent(data).split(':');
     const iv = Buffer.from(ivHex, 'base64');
     const encrypted = Buffer.from(encryptedHex, 'base64');