ENCRYPTBYCERT (Transact-SQL)

Encrypts data with the public key of a certificate.

Topic link iconTransact-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 [AdventureWorks].[ProtectedData04] 
    values( N'data encrypted by certificate ''Shipping04''',
    EncryptByCert(Cert_ID('JanainaCert02'), @cleartext) );
GO