Vaults

The Keymaster’s vault (Vault of Secrets)
Requiring 50 diamonds to get in, it is easier to access than the Guard’s one. You just need to hit the lock on the top of the Online Levels section.

The Guard’s Vault (The Vault)
Requiring 10 user coins to get in, it is found on the top of the settings section.

Code Icons
If you want to see them, just go into the game and enter all the hint codes.