signbyasymkey-transact-sql.md

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SIGNBYASYMKEY (Transact-SQL)	SIGNBYASYMKEY (Transact-SQL)	VanMSFT	vanto	03/06/2017	sql	t-sql	reference	SIGNBYASYMKEY_TSQL SIGNBYASYMKEY	text signing [SQL Server] encryption [SQL Server], asymmetric keys signing text [SQL Server] SIGNBYASYMKEY function asymmetric keys [SQL Server], SIGNBYASYMKEY function cryptography [SQL Server], asymmetric keys clear text signing	TSQL

SIGNBYASYMKEY (Transact-SQL)

[!INCLUDE SQL Server Azure SQL Database Azure SQL Managed Instance]

Signs plaintext with an asymmetric key

:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: Transact-SQL syntax conventions

Syntax

SignByAsymKey( Asym_Key_ID , @plaintext [ , 'password' ] )  

Arguments

Asym_Key_ID
Is the ID of an asymmetric key in the current database. Asym_Key_ID isint.

@plaintext
Is a variable of type nvarchar, char, varchar, or nchar containing data that will be signed with the asymmetric key.

password
Is the password with which the private key is protected. password is nvarchar(128).

Return Types

varbinary with a maximum size of 8,000 bytes.

Remarks

Requires CONTROL permission on the asymmetric key.

Examples

The following example creates a table, SignedData04, in which to store plaintext and its signature. It next inserts a record in the table, signed with asymmetric key PrimeKey, which is first decrypted with password 'pGFD4bb925DGvbd2439587y'.

-- Create a table in which to store the data  
CREATE TABLE [SignedData04](Description NVARCHAR(max), Data NVARCHAR(max), DataSignature VARBINARY(8000));  
GO  
-- Store data together with its signature  
DECLARE @clear_text_data NVARCHAR(max);  
set @clear_text_data = N'Important numbers 2, 3, 5, 7, 11, 13, 17,   
      19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79,  
      83, 89, 97';  
INSERT INTO [SignedData04]   
    VALUES( N'data encrypted by asymmetric key ''PrimeKey''',  
    @clear_text_data, SignByAsymKey( AsymKey_Id( 'PrimeKey' ),  
    @clear_text_data, N'pGFD4bb925DGvbd2439587y' ));  
GO  

See Also

ASYMKEY_ID (Transact-SQL)
VERIFYSIGNEDBYASYMKEY (Transact-SQL)
CREATE ASYMMETRIC KEY (Transact-SQL)
ALTER ASYMMETRIC KEY (Transact-SQL)
DROP ASYMMETRIC KEY (Transact-SQL)
Encryption Hierarchy