Policy: A set of guidelines or rules that dictate how a company or organization should handle certain situations or processes. Policies are often used to ensure compliance with regulations and to protect the security and integrity of an organization's data and systems. Examples of policies include an employee password policy, a data retention policy, and a policy for handling confidential information.

Policy Approving Authority (PAA): A Policy Approving Authority (PAA) is a designated official or governing body within an organization that has the authority to formally approve and endorse policies. The PAA is responsible for ensuring that policies are suitable for the organization's needs and comply with relevant laws and regulations. Their approval signifies that the policy meets the organizational standards for managing risks and aligns with its strategic objectives.

Policy Certification Authority (PCA): An entity within a Public Key Infrastructure (PKI) responsible for defining, implementing, and enforcing policies and practices related to the issuance and management of digital certificates. The PCA sets standards and requirements for subordinate Certification Authorities (CAs) to ensure they operate under a common framework, maintaining the trust and reliability of the digital certificates within the PKI, and supporting secure electronic transactions.

Polymorphic/Polymorphism: A technique that enables malicious code or software to alter its identifiable traits while maintaining its core functionality, making it difficult for security tools that rely on specific signatures or patterns to detect it. This method is commonly employed by malware, such as viruses and worms, to evade detection and remain stealthy within a network or system.

Polymorphic virus: A polymorphic virus is a type of malware that can alter its code or signature on each infection, making it difficult for antivirus programs to recognize and remove it using signature-based detection. The virus retains its primary payload but changes how it appears to security programs, thus increasing its chances of spreading without being intercepted.

Population: The total number of people or items in a specific group or area. In cybersecurity, it refers to the number of potential targets for an attack, such as the number of computers on a network or users of a particular software application.