Q1:

Q2:

1. Authentication

• Ensures only authorized users can access the database.

• Techniques:
• Username and password.
• Multi-factor authentication (e.g., a code sent to a phone).
• Biometric systems (e.g., fingerprint or face recognition).

2. Authorization

• Determines what actions authenticated users are allowed to perform.

• Example: Different levels of access for administrators, users, and guests:
• Admin: Full access (read/write/delete).
• User: Limited access (read/write).
• Guest: View-only access.

3. Encryption

• Protects data by converting it into a coded format that is unreadable without a decryption key.

• Use Cases:
• Encrypting sensitive data like passwords or financial details.
• Securing data during transmission over networks.

4. Backups

• Regular backups ensure data can be recovered in case of loss or corruption.

• Backups should be stored securely and, ideally, offsite or in the cloud.

5. Firewalls and Network Security

• Firewalls restrict unauthorized access to the database from external networks.

• Security measures like Virtual Private Networks (VPNs) and Secure Sockets Layer (SSL) can provide additional protection.

6. Input Validation

• Ensures data entered into the database is safe and conforms to expected formats.

• Protects against SQL injection attacks, where malicious SQL code is entered to manipulate or compromise the database.

7. Audit Trails

• Maintains logs of database activities to monitor for unusual or unauthorized actions.

• Helps in detecting and investigating security breaches.

8. Access Control

• Uses roles and permissions to restrict database operations.

• Example: A student in a university system should not have access to administrative or financial records.

9. Physical Security

• Protects database servers from physical threats such as theft or damage.

• Measures: Secure server rooms, biometric locks, and CCTV surveillance.

10. Software Updates and Patches

• Keeps database management systems (DBMS) updated to address known vulnerabilities.

• Minimizes risk from exploits targeting outdated software.

Common Threats

• SQL Injection: Exploiting vulnerabilities in input validation.

• Unauthorized Access: Gaining access to sensitive data without proper credentials.

• Data Breaches: Theft or exposure of private data.

• Data Corruption: Accidental or intentional alteration of data.

1. Each cell contains a single value (atomicity): Multi-valued fields (like Subject and SubjectCode) must be removed.

2. Each record is unique: A unique identifier (Primary Key) is added.

Steps to Modify the Table

1. Remove Multi-Valued Fields

2. Create a Unique Identifier

3. Restructure the Table

Normalized Table in 1NF

Key Changes

1. Multi-valued attributes (Subject and SubjectCode) are split into separate rows.

2. A unique identifier (StudentID) is added to ensure each row can be uniquely identified.

3. The table structure ensures atomicity and adheres to the 1NF principle.

Q3:

Application

Justification

Q4:(略)

Q5:

Q6:

Key Differences:

1. Addressing: IPv6 provides a virtually unlimited address pool compared to IPv4.

2. Efficiency: IPv6 has a simplified header and better routing efficiency.

3. Security: IPv6 inherently supports modern security standards.

4. Transition: Mechanisms like dual-stack and tunneling facilitate IPv4 to IPv6 migration.

1. Improved network security: Subnetting allows administrators to isolate sensitive parts of the network, reducing unauthorized access and containing potential security breaches within a specific subnet.

2. Better network performance: Subnetting minimizes congestion by reducing the size of the broadcast domain, which decreases the amount of broadcast traffic and enhances overall network efficiency.

1. Detect collision: Devices monitor the transmission medium to detect if a collision occurs by checking for signal irregularities.

2. Send a jam signal: When a collision is detected, a jam signal is sent to inform all devices on the network about the collision.

3. Backoff and retransmit: Devices stop transmitting, wait for a random backoff period, and then attempt to retransmit the data to avoid further collisions.

Q7: Assembly Language

Q8:Codes

Q9: Codes