Pretty Good Privacy (PGP) Cryptosystem: A data encryption and decryption program used for securing the privacy of email communications, files, and data storage. PGP uses a combination of symmetric-key cryptography and public-key cryptography to offer confidentiality, authentication, and integrity checking of data. It's widely regarded for its capability to provide robust security for digital communication, making it a popular choice for protecting sensitive email content.

Preventive: Preventive measures in cybersecurity are actions and strategies implemented to stop security incidents before they occur. These measures are based on the anticipation of potential threats and include practices like installing firewalls, enforcing strong authentication protocols, conducting regular security training, and applying timely system patches. Their aim is to enhance the overall security posture and prevent the exploitation of vulnerabilities.

Preventive control: Security measures designed to prevent undesirable events, such as data breaches or system intrusions. These controls work by deterring potential incidents before they occur, serving as a proactive method for enhancing system security. Examples of preventive controls include firewalls, access controls, encryption, and security awareness training. By implementing preventive controls, organizations can reduce their vulnerability to potential threats and protect their valuable resources.

Primary key: A unique identifier for a record in a database table. Each table has one primary key, which cannot have null values and must contain unique values. This ensures that each record in a table can be uniquely identified, providing a way to retrieve, update, or delete specific records efficiently. By enforcing uniqueness and integrity, the use of primary keys is vital for maintaining organized and efficient database systems.

Primary site: The main location where an organization's data and operations are based, crucial for disaster recovery planning to ensure service continuity. Examples include a company's headquarters or a government agency's main office.

Prime number: A natural number greater than 1 that has no positive divisors other than 1 and itself. In other words, it can only be divided evenly by 1 and the number itself. Prime numbers are fundamental to various fields of mathematics and are especially important in number theory. In the context of IT and cybersecurity, prime numbers are crucial for cryptographic algorithms, particularly those involving public-key cryptography such as RSA, where large prime numbers are used to generate secure encryption keys.