The five defined maturity levels of the CMM are:
Initial, repeatable, defined, managed and optimizing.
Reference used for this question:
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten
Domains of Computer Security, John Wiley & Sons, 2001, Chapter 7: Applications and Systems
Development (page 254).

Defense in depth is a layered security strategy that employs multiple overlapping controls (physical, technical, and administrative) across different levels of the environment, so that the failure or bypass of a single control does not result in a complete security breach.

Encryption is the process of transforming data into an unreadable format using a secret key or algorithm. Encryption ensures the confidentiality, integrity, and availability of the data, and protects it from unauthorized access, modification, or deletion. Encryption is also a requirement of the GDPR, which is a legal framework that sets guidelines for the collection and processing of personal data of individuals within the EU.

"Identification is the process by which a subject professes an identify and accountability is initiated." Pg 149 Tittel: CISSP Study Guide
"Identification and authentication are the keystones of most access control systems. Identification is the act of a user professing an identify to a system, usually in the form of a log-on ID to the system. Identification establishes user accountability for the actions on the system. Authentication is verification that the user's claimed identity is valid and is usually implemented through a user password at log-on time." Pg 36 Krutz: The CISSP Prep Guide