KEY_NAME (Transact-SQL)

บทความ
09/03/2024

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance

Returns the name of the symmetric key from either a symmetric key GUID or cipher text.

Syntax

KEY_NAME ( ciphertext | key_guid )

Arguments

ciphertext
Is the text encrypted by the symmetric key. cyphertext is type varbinary(8000).

key_guid
Is the GUID of the symmetric key. key_guid is type uniqueidentifier.

Returned Types

varchar(128)

Permissions

Beginning in SQL Server 2005 (9.x), the visibility of metadata is limited to securables that a user either owns or on which the user has been granted some permission. For more information, see Metadata Visibility Configuration.

Examples

A. Displaying the name of a symmetric key using the key_guid

The master database contains a symmetric key named ##MS_ServiceMasterKey##. The following example gets the GUID of that key from the sys.symmetric_keys dynamic management view, assigns it to a variable, and then passes that variable to the KEY_NAME function to demonstrate how to return the name that corresponds to the GUID.

USE master;  
GO  
DECLARE @guid uniqueidentifier ;  
SELECT @guid = key_guid FROM sys.symmetric_keys  
WHERE name = '##MS_ServiceMasterKey##' ;  
-- Demonstration of passing a GUID to KEY_NAME to receive a name  
SELECT KEY_NAME(@guid) AS [Name of Key];

B. Displaying the name of a symmetric key using the cipher text

The following example demonstrates the entire process of creating a symmetric key and populating data into a table. The example then shows how KEY_NAME returns the name of the key when passed the encrypted text.

-- Create a symmetric key  
CREATE SYMMETRIC KEY TestSymKey   
   WITH ALGORITHM = AES_128,  
   KEY_SOURCE = 'The square of the hypotenuse is equal to the sum of the squares of the sides',  
   IDENTITY_VALUE = 'Pythagoras'  
   ENCRYPTION BY PASSWORD = 'pGFD4bb925DGvbd2439587y' ;  
GO  
-- Create a table for the demonstration  
CREATE TABLE DemoKey  
(IDCol INT IDENTITY PRIMARY KEY,  
SecretCol VARBINARY(256) NOT NULL)  
GO  
-- Open the symmetric key if not already open  
OPEN SYMMETRIC KEY TestSymKey   
    DECRYPTION BY PASSWORD = 'pGFD4bb925DGvbd2439587y';  
GO  
-- Insert a row into the DemoKey table  
DECLARE @key_GUID uniqueidentifier;  
SELECT @key_GUID = key_guid FROM sys.symmetric_keys  
WHERE name LIKE 'TestSymKey' ;  
INSERT INTO DemoKey(SecretCol)  
VALUES ( ENCRYPTBYKEY (@key_GUID, 'EncryptedText'))  
GO  
-- Verify the DemoKey data  
SELECT * FROM DemoKey;  
GO  
-- Decrypt the data  
DECLARE @ciphertext VARBINARY(256);  
SELECT @ciphertext = SecretCol  
FROM DemoKey WHERE IDCol = 1 ;  
SELECT CAST (  
DECRYPTBYKEY( @ciphertext)  
AS VARCHAR(100) ) AS SecretText ;  
-- Use KEY_NAME to view the name of the key  
SELECT KEY_NAME(@ciphertext) AS [Name of Key] ;

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