This final emerging technology topic connects security, applied systems and modern digital infrastructure. PSC questions often ask cryptography types, authentication, network attacks, e-commerce security, embedded systems, multimedia compression, GIS layers and GPS positioning.

Concept Teaching

Security protects data and services; embedded systems bring computing into devices; multimedia handles audio/video/image data; GIS/GPS connect computing with geographic space. The exam expects definitions, mechanisms, applications and key tradeoffs.

Cryptography Basics

Cryptography provides security services.

Network Security

Security is layered.

• Confidentiality prevents unauthorized disclosure.
• Integrity prevents unauthorized modification.
• Availability keeps service usable.
• Authentication verifies identity.
• Authorization grants permissions.
• Firewall filters traffic by policy.
• IDS/IPS detects or blocks suspicious activity.
• VPN creates secure tunnel over untrusted network.

E-Commerce Security

E-commerce needs trust, privacy and transaction integrity.

• TLS protects web communication.
• Digital certificates bind public key to identity.
• Payment systems need authentication and fraud controls.
• Non-repudiation prevents denial of transaction origin.
• PCI-style controls protect card data.
• Secure session and input validation prevent common web attacks.

Embedded and Multimedia

Embedded systems and multimedia are application-heavy.

• Embedded systems have constraints: real-time, power, memory and reliability.
• Microcontroller integrates CPU, memory and I/O peripherals.
• RTOS provides deterministic scheduling for real-time tasks.
• Multimedia includes text, image, audio, video and animation.
• Compression reduces storage/bandwidth; lossy trades quality for size.
• JPEG, MP3 and MPEG are common compression examples.

GIS and GPS

Geospatial systems combine location, layers and analysis.

• GIS stores spatial and attribute data.
• Vector data represents points, lines and polygons.
• Raster data represents grid/cell values.
• Layers combine roads, land use, population and infrastructure.
• GPS receiver estimates position using signals from multiple satellites.
• Triangulation/trilateration concept is central to positioning.

Engineering Mechanism

• Security identifies asset and threat.
• Cryptographic protocol applies keys, hashes or signatures.
• Network defenses filter, monitor and encrypt traffic.
• E-commerce system authenticates users and protects transactions.
• Embedded system senses/controls dedicated device.
• Multimedia system captures, compresses and renders media.
• GIS/GPS stores and computes location-based information.

Diagrams / Models To Draw

• Draw symmetric vs asymmetric encryption.
• Draw digital signature flow.
• Draw firewall/IDS/VPN network security layout.
• Draw embedded system sensor-controller-actuator loop.
• Draw GIS layers stack.
• Draw GPS satellites to receiver positioning idea.

Formulas, Algorithms and Rules

• CIA triad = confidentiality + integrity + availability.
• Digital signature = hash message, encrypt hash with private key conceptually.
• Symmetric crypto is fast but key distribution is hard.
• Asymmetric crypto helps key exchange/signatures but is slower.
• Compression ratio = original size / compressed size.

Worked Example

In online payment, browser verifies server certificate, establishes TLS session key, encrypts transaction data, server authenticates request and payment gateway records transaction. Hashes/signatures may protect integrity and non-repudiation.

Subjective Answer Pattern

• Define cryptography/security goals.
• Compare symmetric/asymmetric/hash/signature.
• Explain network and e-commerce security controls.
• Discuss embedded system features.
• Explain multimedia compression.
• Differentiate GIS and GPS with applications.

Common Engineering Mistakes

• Saying hash can be decrypted.
• Confusing private key and public key use in signature.
• Equating firewall with complete security.
• Confusing GIS with GPS.
• Ignoring embedded resource constraints.
• Saying lossy compression preserves exact original.

MCQ Revision

• What are CIA triad components?
• AES is symmetric or asymmetric?
• Hash is reversible: true or false?
• Digital signature uses which key to sign?
• GIS stores what type of data?
• GPS uses what source for positioning?

Final Summary

• Cryptography provides core security mechanisms.
• Network security protects communication and infrastructure.
• E-commerce depends on authentication, TLS and transaction integrity.
• Embedded systems perform dedicated constrained computing.
• Multimedia uses compression and rendering.
• GIS analyzes spatial data while GPS provides positioning.