1.3
Exchanging Data
Networks, protocols, databases, and web technologies
Compression, encryption and hashingDatabasesNetworksWeb technologies
Lossy compression permanently removes data; lossless is reversible
Symmetric encryption uses same key for encrypt/decrypt
Asymmetric encryption uses public/private key pairs
Normalisation reduces data redundancy (1NF, 2NF, 3NF)
SQL: SELECT, INSERT, UPDATE, DELETE for database operations
TCP/IP model: Application, Transport, Internet, Link layers
Packet switching divides data into packets for transmission
HTML for structure, CSS for styling, JavaScript for interactivity
Exam Tips
- •Always define key terms before explaining concepts
- •Use specific examples where possible to demonstrate understanding
- •Check mark allocation - one point per mark is a good guide