encryptbycert-transact-sql.md

title	ENCRYPTBYCERT (Transact-SQL) | Microsoft Docs
ms.custom
ms.date	03/06/2017
ms.prod	sql
ms.prod_service	database-engine, sql-database
ms.reviewer
ms.technology	t-sql
ms.topic	language-reference
f1_keywords	ENCRYPTBYCERT ENCRYPTBYCERT_TSQL
dev_langs	TSQL
helpviewer_keywords	certificates [SQL Server], encryption encryption [SQL Server], certificates ENCRYPTBYCERT function
ms.assetid	ab66441f-e2d2-4e3a-bcae-bcc09e12f3c1
author	MashaMSFT
ms.author	mathoma
manager	craigg

ENCRYPTBYCERT (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-asdb-xxxx-xxx-md]

Encrypts data with the public key of a certificate.

Transact-SQL Syntax Conventions

Syntax

  
EncryptByCert ( certificate_ID , { 'cleartext' | @cleartext } )  

Arguments

certificate_ID
The ID of a certificate in the database. int.

cleartext
A string of data that will be encrypted with the certificate.

@cleartext
A variable of type nvarchar, char, varchar, binary, varbinary, or nchar containing data that will be encrypted with the public key of the certificate.

Return Types

varbinary with a maximum size of 8,000 bytes.

Remarks

This function encrypts data with the public key of a certificate. The ciphertext can only be decrypted with the corresponding private key. Such asymmetric transformations are very costly compared to encryption and decryption using a symmetric key. Asymmetric encryption is therefore not recommended when working with large datasets such as user data in tables.

Examples

This example encrypts the plaintext stored in @cleartext with the certificate called JanainaCert02. The encrypted data is inserted into table ProtectedData04.

INSERT INTO [AdventureWorks2012].[ProtectedData04]   
    VALUES ( N'Data encrypted by certificate ''Shipping04''',  
    EncryptByCert(Cert_ID('JanainaCert02'), @cleartext) );  
GO  

See Also

DECRYPTBYCERT (Transact-SQL)
CREATE CERTIFICATE (Transact-SQL)
ALTER CERTIFICATE (Transact-SQL)
DROP CERTIFICATE (Transact-SQL)
BACKUP CERTIFICATE (Transact-SQL)
Encryption Hierarchy