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Introduction to cryptography - INFO-F-405 - 2. Secret - Coggle Diagram
Introduction to cryptography - INFO-F-405 - 2. Secret
Setting and Key Distribution
Secure Communication
Shared Secret Keys
Distribution Methods
Hand-to-Hand Exchanges
Smart Cards
Key Establishment Schemes
Participants
Alice and Bob: Communicators
Oscar: Eavesdropper
Keystream Generators and Stream Ciphers
Stream Ciphers
XOR Operation with Plaintext
XOR Operation with Ciphertext
Linear Feedback Shift Register (LFSR)
Feedback Polynomial
Examples
Trivium: Robust Stream Cipher
RC4: Popular but Vulnerable
Block Ciphers
Concept
Maps Secret Key and Input to Output
Reversible for Decryption
Security Notions
Pseudo-Random Permutation (PRP)
Strong PRP (SPRP)
DES
Feistel Network
Weaknesses: Differential & Linear Cryptanalysis
Triple-DES
Enhanced Security
112/168-bit Key Length
Advanced Encryption Standard (AES)
Rijndael Cipher
Key Sizes: 128, 192, 256 bits
Transformation Rounds
SubBytes: S-Box Substitution
ShiftRows: Byte Shifting
MixColumns: Matrix Multiplication
AddRoundKey: Key Addition
Galois Field (GF 2^8)
Finite Field Arithmetic
Modes of Operation
ECB
Independent Block Encryption
Weakness: Reveals Patterns
CBC
XOR Plaintext with Previous Ciphertext
CTR
Encrypts Sequential Counter Values
CBC-MAC
Last Ciphertext Block as MAC
Permutations and Sponge Construction
Permutations
Bijective Mappings
Sponge Construction
Absorbing Input
Squeezing Output
SpongeWrap
Authenticated Encryption and MAC
Authenticated Encryption
Galois/Counter Mode (GCM)
Counter with CBC-MAC (CCM)
Pseudo-Random Functions (PRFs)
Concept
Unpredictable, Secure Outputs
Incremental MACs
Efficient Authentication for Large Data
Core Takeaways
Diverse Techniques
Stream Ciphers: Continuous Data
Block Ciphers: Fixed-Size Data
Layered Security
Use Modes for Encryption and Authentication
Peer Review
Ensures Robustness Against Evolving Attacks
Avoid Weak Modes
Replace ECB with CBC or CTR