Fundamentals of Cryptography

---

Goals

• Define cryptography, including its origins and influencers
• Identify types of cryptography tools, including symmetric, asymmetric, hash functions, digital signatures, and certificates
• Differentiate protecting data at rest, data in motion, and data in use
• Classify security principles and actions according to the types of attacks they mitigate or eliminate
• Classify cybersecurity tools according to the type of vulnerability they find/identify
• Identify cybersecurity concepts and principles that protect critical information (e.g., intellectual property, files)
• Categorize types of cryptography tools according to the leg of the CIA triad they enforce

Cryptography is the science of protecting the confidentiality and integrity of data.

• Core aspects
  • confidentiality: prevents unauthorized disclosure of data
  • integrity: ensures data isn’t modified
  • authentication: used to validate sender with digital signatures
  • nonrepudiation: digital signatures can prove identity and actions

Encryption is the process of transforming readable data, called plaintext or cleartext, into an unreadable form called ciphertext.

Decryption is the process of recovering the plaintext message from the ciphertext.

Cryptographic algorithm is the specific computational procedure used to encrypt plaintext or decrypt ciphertext.

Key is a password used by algorithms to encrypt and decrypt contents.

History of Cryptography

• Caesar Cipher
• Cryptographic Machines
• Kerckhoff’s Principles
• Transitioning to the Modern Day

Modern Cryptographic Tools

• One-Way Function

Types of Cryptography

Most cryptographic algorithms are sorted into three types:

• Symmetric Encryption
• Asymmetric Encryption
• Hash Functions

Using Cryptography

• Digital Signature
• Digital Certificate

Protecting Data at Rest, in Motion, and in Use

• 3 uses for cryptography:
  • protecting data at rest
  • protecting data in motion
  • protecting data in use