Using Certificates to Encrypt Data
Certificates are parallel with asymmetric keys in the SQL Server 2005 encryption hierarchy. A certificate is simply a method of using asymmetric encryption. Certificates bind public keys to individuals who hold the associated private key. Certificates use the same RSA algorithm as asymmetric keys; therefore, they are resource-intensive and their use is normally restricted to encrypting other keys. SQL Server contains an integrated certificate authority, which it uses to issue its own selfsigned, and industry standard X.509 certificates. Alternatively, you can import certificates from an external certificate authority.The use of external certificates allows you to use a wider range of key lengths, which can provide enhanced security. Certificates are the most secure way in which to encrypt data natively within SQL Server 2005.You can use the CREATE CERTIFICATE statement to create a certificate within SQL Server 2005.