update

Author: mrbullwinkle

articles/ai-services/openai/encrypt-data-at-rest.md

@@ -6,7 +6,7 @@ author: mrbullwinkle
 manager: nitinme
 ms.service: azure-ai-openai
 ms.topic: conceptual
-ms.date: 03/27/2025
+ms.date: 04/17/2025
 ms.author: mbullwin
 ---
 
@@ -39,6 +39,9 @@ Only RSA and RSA-HSM keys of size 2048 are supported with Azure AI services encr
 
 ### Enable your Azure OpenAI resource's managed identity
 
+> [!NOTE]
+> Azure OpenAI only supports customer-managed keys (CMK) with system-assigned managed identities. User-assigned managed identities are not supported with Azure OpenAI and customer-manged keys (CMK).
+
 1. Go to your Azure AI services resource.
 1. On the left, under **Resource Management**, select **Identity**.
 1. Switch the system-assigned managed identity status to **On**.