Security+ Flashcards

Security+ Formulas

Cryptography

Description Formula
Symmetric Encryption (Encryption) E(K, P) = C
Symmetric Encryption (Decryption) D(K, C) = P
Asymmetric Encryption (Encryption with Public Key) E(Pub, P) = C
Asymmetric Encryption (Decryption with Private Key) D(Pr, C) = P
Hash Function H(P) = h
Digital Signature (Signing) S(Pr, M) = Sig
Digital Signature (Verification) V(Pub, M, Sig) = True or False
Key Exchange (Diffie-Hellman) gx mod p, gy mod p

Network Security

Description Formula / Concept
Firewall Rule (Source IP, Destination IP, Port, Protocol, Action)
Access Control List (ACL) (Subject, Object, Operation, Permission)
Annualized Loss Expectancy (ALE) ALE = SLE * ARO
Single Loss Expectancy (SLE) SLE = Asset Value * Exposure Factor
Annualized Rate of Occurrence (ARO) Number of incidents per year
Risk Risk = Threat * Vulnerability
Exposure Factor (EF) Percentage of asset loss caused by a threat
VPN (Encapsulation) Original Packet + Encrypted Payload + New Header

Security Concepts

Concept Description
CIA Triad Confidentiality, Integrity, Availability
Authentication Verifying the identity of a user, device, or other entity.
Authorization Granting or denying access to resources based on identity and permissions.
Accounting (Auditing) Tracking and logging user and system activities.
Non-Repudiation Ensuring that a user cannot deny having performed an action.
Least Privilege Granting users only the necessary permissions to perform their job functions.
Defense in Depth Implementing multiple layers of security controls.
Separation of Duties Dividing critical tasks among multiple individuals to prevent fraud or error.
Incident Response A set of procedures for detecting, responding to, and recovering from security incidents.
Disaster Recovery A plan for restoring critical business functions after a disaster.
Business Continuity A plan for maintaining business operations during and after a disruptive event.
Single Point of Failure (SPOF) A component whose failure will bring down an entire system
Recovery Time Objective (RTO) Maximum acceptable downtime before recovery
Recovery Point Objective (RPO) Maximum acceptable data loss in an incident
Mean Time to Repair (MTTR) Average time to repair a failed component or system
Mean Time Between Failures (MTBF) Average time between failures of a component or system