ENCRYPTBYCERT (Transact-SQL)

Article
08/10/2023

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

Encrypts data with the public key of a certificate.

Syntax

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

Note

To view Transact-SQL syntax for SQL Server 2014 (12.x) and earlier versions, see Previous versions documentation.

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 one of the following types that contains data that will be encrypted with the public key of the certificate:

nvarchar
char
varchar
binary
varbinary
nchar

Return Types

varbinary with a maximum size of 8,000 bytes.

Remarks

This function encrypts data with the certificate's public key. The ciphertext can only be decrypted with the corresponding private key. These asymmetric transformations are costly when compared to encryption and decryption using a symmetric key. As such, asymmetric encryption isn't recommended when working with large datasets.

Examples

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

INSERT INTO [AdventureWorks2022].[ProtectedData04]   
    VALUES ( N'Data encrypted by certificate ''Shipping04''',  
    EncryptByCert(Cert_ID('JanainaCert02'), @cleartext) );  
GO