Computer Protocols- TCP/IP, POP, SMTP, HTTP, FTP and More. In order for computers to communicate with one another, standard methods of information transfer and processing have been devised. These are referred to as protocols and some of the more common ones such as TCP, IP, UDP, POP, SMTP, HTTP, and FTP are discussed here.
One of the possible uses for this function is as a hash key. See the notes at the beginning of this section about storing hash values efficiently. You can also use SHA1() as a cryptographic function for storing passwords. SHA() is synonymous with SHA1() .
Using encryption keys at instance/database level : SQL Server has two kinds of keys: symmetric and asymmetric. Symmetric keys use the same password to encrypt and decrypt data. Asymmetric keys use one password to encrypt data (called the public key) and another to decrypt data (called the private key).