What is "vault" in step 2 for the Zoho Vault API?

Here is the code snippet provided in the documentation:

var masterKey = null;

var passphrase = "user_passphrase"; if(LOGINTYPE == "PBKDF2_AES"){

var masterKey = Vault.PBKDF2_key(passphrase, SALT, ITERATION); }else{

var masterKey = Vault.hash(passphrase);

var passAuth = Vault.hash(passphrase+SALT); }

What is "Vault" in the statement "Vault.PBKDF2_key"? Is it a library, or an object? And how do I get it? Is it possible to provide a more complete program insteaad of the snippet?