signbyasymkey-transact-sql.md

title	SIGNBYASYMKEY (Transact-SQL) | Microsoft Docs
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SIGNBYASYMKEY (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-asdb-xxxx-xxx_md]

Signs plaintext with an asymmetric key

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