What are the secret codes for the vault?

I'm curious, could you elaborate on the secret codes for the vault? Are they a series of alphanumeric characters, or do they involve more complex encryption methods? Are they unique to each vault, or are there standard protocols that are followed? And most importantly, how secure are these codes in protecting the valuable assets stored within the vault? I'm eager to understand the intricacies of this security measure and how it contributes to the overall safety and security of cryptocurrency holdings.