What is Cryptography?

Cryptography is the science of protecting information by transforming it into an unreadable format. It encompasses various techniques and algorithms to ensure data confidentiality, integrity, and authenticity.

Key Cryptographic Concepts

Confidentiality: Information accessible only to authorized parties
Integrity: Information hasn't been altered
Authentication: Confirms identity of parties
Non-repudiation: Cannot deny sending a message

Types of Cryptography

Symmetric Key Cryptography
Asymmetric Key Cryptography
Hash Functions

Symmetric Key Cryptography

Characteristics:

Same key for encryption and decryption
Fast and efficient for large data
Key management challenge

Examples:

AES: Advanced Encryption Standard
DES: Data Encryption Standard (obsolete)

Asymmetric Key Cryptography

Characteristics:

Public and private key pair
Easier key management
Computationally more intensive

Examples:

RSA: Rivest-Shamir-Adleman
ECC: Elliptic Curve Cryptography

Hash Functions

Characteristics:

Fixed-size output for any input
One-way function
Used for data integrity

Examples:

SHA-256: Secure Hash Algorithm
MD5: Message Digest (weak)

Cryptographic Protocols

SSL/TLS: Secure web communications
PGP: Pretty Good Privacy for email
IPsec: Secure IP communications
SSH: Secure Shell for remote access

Digital Signatures

Purpose: Ensures authenticity and integrity of messages

Process:

Hash the message
Encrypt hash with private key
Attach signature to message
Receiver verifies with public key

Key Exchange

Challenge: How to securely share keys over insecure channels?

Solutions:

Diffie-Hellman: Key exchange protocol
RSA Key Exchange: Using public key encryption
ECDH: Elliptic Curve Diffie-Hellman

Cryptography Applications

Secure Communication: HTTPS, email encryption
Data Protection: Disk encryption, databases
Authentication: Digital certificates, passwords
Blockchain: Cryptocurrencies, smart contracts
Network Security: VPNs, firewalls

Cryptography Challenges

Quantum Computing: Threat to current algorithms
Key Management: Secure storage and distribution
Implementation Flaws: Security vulnerabilities
Performance: Balancing security and speed

Quantum Computing Impact

Warning: Quantum computers could break current public key cryptography

Response:

Post-quantum cryptography research
Quantum-resistant algorithms
Hybrid security approaches

Cryptography Best Practices

Use well-tested, standard algorithms
Implement proper key management
Regular security updates
Follow principle of least privilege
Monitor for vulnerabilities

Key Takeaways

Cryptography is foundation of modern security
Three main types: symmetric, asymmetric, hash
Each type serves specific purposes
Key management is critical
Quantum computing poses future challenges

Remember: Security is only as strong as the weakest link

Thank You

Questions & Discussion

Next: Symmetric vs Asymmetric Encryption