--- title: "Symmetric Keys on User Databases | Microsoft Docs" ms.custom: "" ms.date: "06/13/2017" ms.prod: "sql-server-2014" ms.reviewer: "" ms.technology: security ms.topic: conceptual helpviewer_keywords: - "Best Practices [Database Engine]" ms.assetid: 3333ab5b-2518-4753-a0a8-57df5e5af74f author: MikeRayMSFT ms.author: mikeray manager: craigg --- # Symmetric Keys on User Databases This rule checks whether keys that have a length of less than 128 bytes do not use the RC2 or RC4 encryption algorithm. ## Best Practices Recommendations Use AES 128 bit or larger to create symmetric keys for data encryption. If AES is not supported by your operating system, use 3DES. ## For More Information [Choose an Encryption Algorithm](../security/encryption/choose-an-encryption-algorithm.md) ## See Also [Monitor and Enforce Best Practices by Using Policy-Based Management](monitor-and-enforce-best-practices-by-using-policy-based-management.md)