A key store is an input component for the PXEService to manage keys securely. It provides a secure environment and interfaces for users to manage their keys. When the PXEService requests keys and signatures from the key store, a well-designed key store should prompt users to authorize the requested action before sending any sensitive information to the PXEService. This helps to ensure that sensitive data, such as private keys, is not accessible to unauthorized parties. Additionally, the key store should provide robust protection mechanisms such as encryption, multi-factor authentication, and backup/restore functionalities to prevent data loss or theft.