# Systems and Security : Architecture and Design

**1.8 Summarize the basics of cryptographic concepts.**

Cryptography is the practice of using mathematical algorithms to protect information by converting it into an unreadable format. The main cryptographic concepts include:

**1. Encryption:** the process of converting plaintext into ciphertext, which is unreadable without the proper decryption key.

**2. Key management:** the process of generating, storing, and distributing keys used for encryption and decryption.

**3. Symmetric encryption:** uses a single key to encrypt and decrypt data.

**4. Asymmetric encryption:** uses two keys, one for encryption and one for decryption.

**5. Hash functions:** a one-way mathematical function that takes an input (or "message") and returns a fixed-sized string of characters, which is unique to that input.

**6. Digital signatures:** a mathematical proof used to verify the authenticity of a digital message or document.

**7. Certificates: **digital documents that bind a public key to the identity of an individual, organization, or device.

**8. Public key infrastructure (PKI):** a system that manages public keys and digital certificates, and provides secure communication between parties.

**9. Key exchange:** the process of securely exchanging encryption keys between two parties.

**10. Cryptographic protocols:** established procedures that specify how encryption and decryption are performed in a secure manner.