Lesson Plan

Course:	Principles of Cybersecurity
Lesson:	Introduction to Cryptography
Intensity:	Medium
Duration:	0.5 hours

LEARNING OBJECTIVES

• Name all key terms with their definition

• Recite one or more historical cryptographic ciphers

• Compare and contrast symmetric and asymmetric cryptography

• Explain the use of cryptographic hashing

SUMMARY OF TASKS

Important Definitions

• Define cryptography and cryptanalysis

• Define key terms

  • Cipher

  • Key

  • Plaintext

  • Ciphertext

  • Encrypt

  • Decrypt

• Discuss why we use cryptography today

  • Ensure confidentiality and integrity of our data

    Origins of Cryptography

• Discuss the history of cryptography

  • Started with transposition ciphers

    • Give example

    • Julius Caesar invented the 'Caesar Cipher'

  • Substitution cipher

    • Give example

  • The art of hiding in plain sight (steganography)

    • Ancient times a slave's head would be tattooed and concealed with the regrown hair

    • Others used invisible ink, microdots

  • Discuss the use of the Enigma during WWII

    • Alan Turing was one of the cryptanalysts and broke the Enigma

Modern Cryptography

• Discuss using crypto for confidentiality

• Discuss modern crytography

  • Symmetric Cryptography (Secret Key)

    • Purpose: bulk data encryption

    • Key size: 64-512 bits

    • Key distribution: one key per com channel

    • Common algorithms: DES, AES, RC4

    • Discuss simple encryption example

  • Asymmetric Cyptography (Public-key)

    • Purpose: small data encryption and digital signing

    • Key size: 2048-4096 bits

    • Key distribution: one private, one public key

    • Common algorithms: RSA, DSA

    • Discuss simple encryption example

    • Discuss simple digital signature example

  • Discuss the problems with each

    • Symmetric - needs a key for each communication channel

    • Asymmetric - difficult to setup and needs significant infrastructure

  • Discuss using crypto for integrity

    • Discuss cryptographic hashing

EVALUATION CRITERIA

Students will take a five question quiz for this module

RESOURCES

Crypto Corner - Transposition Ciphers Crypto Corner - Caesar Shift Cipher

REFERENCES

Cryptography - Wikipedia Cryptanalysis - Wikipedia The Enigma - Wikipedia Alan Turing - Wikipedia