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title: "sys.symmetric_keys (Transact-SQL) | Microsoft Docs"
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# sys.symmetric_keys (Transact-SQL)
[!INCLUDE[tsql-appliesto-ss2008-all_md](../../includes/tsql-appliesto-ss2008-all-md.md)]

  Returns one row for every symmetric key created with the CREATE SYMMETRIC KEY statement.  
  
|Column name|Data type|Description|  
|-----------------|---------------|-----------------|  
|**name**|**sysname**|Name of the key. Unique within the c4database.|  
|**principal_id**|**int**|ID of the database principal who owns the key.|  
|**symmetric_key_id**|**int**|ID of the key. Unique within the database.|  
|**key_length**|**int**|Length of the key in bits.|  
|**key_algorithm**|**char(2)**|Algorithm used with the key:<br /><br /> R2 = RC2<br /><br /> R4 = RC4<br /><br /> D = DES<br /><br /> D3 = Triple DES<br /><br /> DT = TRIPLE_DES_3KEY<br /><br /> DX = DESX<br /><br /> A1 = AES 128<br /><br /> A2 = AES 192<br /><br /> A3 = AES 256<br /><br /> NA = EKM Key|  
|**algorithm_desc**|**nvarchar(60)**|Description of the algorithm used with the key:<br /><br /> RC2<br /><br /> RC4<br /><br /> DES<br /><br /> Triple_DES<br /><br /> TRIPLE_DES_3KEY<br /><br /> DESX<br /><br /> AES_128<br /><br /> AES_192<br /><br /> AES_256<br /><br /> NULL (Extensible Key Management algorithms only)|  
|**create_date**|**datetime**|Date the key was created.|  
|**modify_date**|**datetime**|Date the key was modified.|  
|**key_guid**|**uniqueidentifier**|Globally unique identifier (GUID) associated with the key. It is auto-generated for persisted keys. GUIDs for temporary keys are derived from the user-supplied pass phrase.|  
|**key_thumbprint**|**sql_variant**|SHA-1 hash of the key. The hash is globally unique. For non-Extensible Key Management keys this value will be NULL.|  
|**provider_type**|**nvarchar(120)**|Type of cryptographic provider:<br /><br /> CRYPTOGRAPHIC PROVIDER = Extensible Key Management keys<br /><br /> NULL = Non-Extensible Key Management keys|  
|**cryptographic_provider_guid**|**uniqueidentifier**|GUID for the cryptographic provider. For non-Extensible Key Management keys this value will be NULL.|  
|**cryptographic_provider_algid**|**sql_variant**|Algorithm ID for the cryptographic provider. For non-Extensible Key Management keys this value will be NULL.|  
  
## Permissions  
 [!INCLUDE[ssCatViewPerm](../../includes/sscatviewperm-md.md)] For more information, see [Metadata Visibility Configuration](../../relational-databases/security/metadata-visibility-configuration.md).  
  
## Remarks  
 The RC4 algorithm is deprecated. [!INCLUDE[ssNoteDepFutureDontUse](../../includes/ssnotedepfuturedontuse-md.md)]  
  
> [!NOTE]  
>  The RC4 algorithm is only supported for backward compatibility. New material can only be encrypted using RC4 or RC4_128 when the database is in compatibility level 90 or 100. (Not recommended.) Use a newer algorithm such as one of the AES algorithms instead. In [!INCLUDE[ssSQL11](../../includes/sssql11-md.md)] material encrypted using RC4 or RC4_128 can be decrypted in any compatibility level.  
  
 **Clarification regarding DES algorithms:**  
  
-   DESX was incorrectly named. Symmetric keys created with ALGORITHM = DESX actually use the TRIPLE DES cipher with a 192-bit key. The DESX algorithm is not provided. [!INCLUDE[ssNoteDepFutureAvoid](../../includes/ssnotedepfutureavoid-md.md)]  
  
-   Symmetric keys created with ALGORITHM = TRIPLE_DES_3KEY use TRIPLE DES with a 192-bit key.  
  
-   Symmetric keys created with ALGORITHM = TRIPLE_DES use TRIPLE DES with a 128-bit key.  
  
## See Also  
 [Catalog Views &#40;Transact-SQL&#41;](../../relational-databases/system-catalog-views/catalog-views-transact-sql.md)   
 [Extensible Key Management &#40;EKM&#41;](../../relational-databases/security/encryption/extensible-key-management-ekm.md)   
 [Security Catalog Views &#40;Transact-SQL&#41;](../../relational-databases/system-catalog-views/security-catalog-views-transact-sql.md)   
 [Encryption Hierarchy](../../relational-databases/security/encryption/encryption-hierarchy.md)   
 [CREATE SYMMETRIC KEY &#40;Transact-SQL&#41;](../../t-sql/statements/create-symmetric-key-transact-sql.md)