Computer Science \ Cyber Security

Cyber Security within the field of Computer Science concerns the protection of computer systems, networks, and data from digital attacks, unauthorized access, damage, and data breaches. This discipline encompasses a wide range of practices and principles aimed at safeguarding the integrity, confidentiality, and availability of information and computing infrastructure.

Key Concepts in Cyber Security

1. Confidentiality: Ensuring that sensitive information is only accessible to authorized users and is kept private. Techniques to achieve confidentiality include encryption, access control mechanisms, and data masking.

2. Integrity: Maintaining the accuracy and completeness of data. This involves protecting information from being altered in unauthorized ways. Tools such as cryptographic hash functions and digital signatures are often used to verify integrity.

3. Availability: Ensuring that information and resources are accessible to authorized users when needed. This includes protecting against attacks like Denial-of-Service (DoS) and ensuring redundancy and fault tolerance through backup systems and distributed architectures.

Threats and Attacks

Cyber Security must deal with various threats, including but not limited to:

• Malware: Malicious software like viruses, worms, trojans, and ransomware that can cause damage or unauthorized access to systems.
• Phishing: Deceptive attempts to obtain sensitive information such as usernames, passwords, and credit card details by masquerading as a trustworthy entity.
• Man-in-the-Middle (MitM) Attacks: Eavesdropping attacks where the attacker intercepts and possibly alters the communication between two parties without them knowing.

Defense Mechanisms

To protect against these threats, several defense mechanisms are employed:

1. Cryptography: The science of encoding and decoding information to protect the data’s privacy and integrity. Examples include symmetric-key cryptography (e.g., AES) and public-key cryptography (e.g., RSA).

   • Symmetric-Key Cryptography: Uses the same key for both encryption and decryption. Mathematically, it is defined as:
     \[
     C = E(K, P) \quad \text{and} \quad P = D(K, C)
     \]
     where \(E\) and \(D\) are the encryption and decryption functions, \(K\) is the key, \(P\) is the plaintext, and \(C\) is the ciphertext.

   • Public-Key Cryptography: Uses a pair of keys – a public key for encryption and a private key for decryption:
     \[
     C = E(K_{\text{public}}, P) \quad \text{and} \quad P = D(K_{\text{private}}, C)
     \]

2. Firewalls: Systems designed to prevent unauthorized access to or from a private network by filtering traffic based on predetermined security rules.

3. Intrusion Detection and Prevention Systems (IDPS): Systems that monitor networks and systems for malicious activity or policy violations and can respond to detected intrusions.

4. Multi-Factor Authentication (MFA): An authentication mechanism that requires two or more independent credentials for a user to gain access to a system.

Advanced Topics

• Penetration Testing: The practice of testing a computer system, network or web application to find vulnerabilities that an attacker could exploit. This is often done using automated tools or manual testing techniques.

• Incident Response: A structured approach to handling security breaches or attacks, including identifying, managing, and recovering from incidents to minimize damage and restore normal operations as quickly as possible.

Cyber Security is a constantly evolving field as attackers develop new techniques and tools, emphasizing the need for continuous learning and adaptation of new technologies and methodologies to protect critical information systems.