If you need to store confidential data in your database, you can use data encryption. SQL Server supports encryption with symmetric keys, asymmetric keys, certificates, and password phrases. Let's first have a theoretical look at each of these encryption techniques.
When you use symmetric key encryption, the party that encrypts the data shares the same key with the party that decrypts the data. Because the same key is used for encryption and decryption, this is called symmetric key encryption. This encryption is very fast. However, if an unauthorized party somehow acquires the key, that party can decrypt the data. Protecting symmetric keys is a challenge. The symmetric key must remain secret. Symmetric encryption is also called secret key encryption.
In asymmetric key encryption, you use two different keys that are mathematically linked. You must keep one key secret and prevent unauthorized access to it; this is the private key. You make the other key public to anyone;...