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Private: NUS NCL – Junior Cybersecurity Olympiad

Cryptography Session 1

Segment 1 Introduction Video

Segment 1: Introduction

Learning Outcome

Table of Content

How to get more

Cryptography Overview

The core problem considered by Cryptography

Types Of Methods

Segment 2 Encryption Video

Segment 2.1: Overview on Encryption

Main idea in Encryption

Segment 2.1: Substitution cipher

Substitution Cipher

Substitution Cipher (Demo in Cyber Chef)

What would an attacker do?

Substitution cipher is not secure

Segment 2.2: Modern cipher

Modern Cipher: AES block cipher

Mode-of-operations

CTR mode (Stream cipher)

CTR mode (Stream cipher)

Background: xor, ⊕

Segment 3 Hash Video

Segment 3: Cryptographic Hash

An application of Hash

What would an attacker do?

Cryptographically secure hash

Message Authentication Code (MAC), Signature

SHA1 Hashing (Demo in Cyberchef Tutorial)

Background: encoding:

Background: ASCII characters

Encoding (Demo)

Segment 4 Pitfall Video

Segment 4: Pitfalls in Cryptography

Can encryption scheme be “hacked”? Pitfalls in cryptography

Segment 4.1: Don’t roll your own crypto

Designing your own Cipher

Segment 4.2: Vulnerable Secret Key Selections

Generate from Weak Password

What is the workload of Exhaustive Search?

Predictable Generation

Segment 4.3: Wrong Mode-of-Operation

Wrong Choice of Mode-of-Operation

ECB Mode- recap

Segment 4.4: Mishandling IV

Pitfall: Mishandling IV

CTR mode (Stream cipher)

CTR mode using the same IV

secure way: Encrypt using 2 different IVs

Mishandling of IV

Segment 4.5: Reliance on Obscurity

Segment 4.6: Pitfall: Side Channel Attack(mistake?)

Side-Channel Attack

Example: Power Consumption

Other Side-Channel Attacks (not limited to crypto)

Segment 5 History Video

Segment 5: Some historical Facts

Cryptography: History

“Failed” Modern Ciphers

Networking Fundamentals Session 2

Segment 1 Introduction Video

Segment 1: Introduction

Learning Outcome

Table of Content

1 of 4

Next Contest Practice Paper

Substitution cipher is not secure

Use frequency analysis. See https://en.wikipedia.org/wiki/Frequency_analysis

© 2024 National Cybersecurity R&D Laboratory (NCL)

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