Section 8 (Cryptography)

Symmetric encryption

Uses one shared key for both encryption and decryption

Asymmetric encryption

Uses a key pair: one public key to encrypt, one private key to decrypt

Public key

Used to encrypt data in asymmetric encryption

Private key

Used to decrypt data in asymmetric encryption

RSA

Common asymmetric encryption algorithm used for secure data transmission

ECC (Elliptic Curve Cryptography)

Asymmetric encryption offering similar security with smaller keys

DES (Data Encryption Standard)

Old symmetric encryption standard, now considered insecure

AES (Advanced Encryption Standard)

Strong symmetric encryption standard used globally

Hashing

One-way function that converts data into a fixed-length string

MD5

Hash algorithm now considered broken due to vulnerabilities

SHA (Secure Hash Algorithm)

Common hashing family; SHA-2 is widely used and secure

HMAC

Hash-based Message Authentication Code; provides data integrity and authenticity

Digital signature

Uses private key to sign a message and public key to verify identity and integrity

Salting

Adding random data to inputs before hashing to prevent rainbow table attacks

Key stretching

Strengthens weak passwords by hashing them multiple times

Birthday attack

Exploits the likelihood of two hashes producing the same output (collision)

Collision attack

Two different inputs result in the same hash output

PKI (Public Key Infrastructure)

System for issuing and managing digital certificates and public keys

Certificate

A digital file that verifies the identity of the certificate holder

Wildcard certificate

Covers all subdomains of a domain (e.g., *.example.com)

Self-signed certificate

Signed by the creator instead of a trusted Certificate Authority

CSR (Certificate Signing Request)

Request sent to a CA to obtain a digital certificate

Root of trust

Trusted entity at the top of the certificate chain hierarchy

CRL (Certificate Revocation List)

List of certificates revoked by a CA before expiration

OCSP (Online Certificate Status Protocol)

Real-time method to check certificate revocation status

Blockchain

Distributed, immutable digital ledger technology

Open public ledger

Public record of transactions viewable by anyone, used in blockchains

TPM (Trusted Platform Module)

Hardware chip that provides secure cryptographic functions

HSM (Hardware Security Module)

Secure hardware device for managing digital keys and crypto operations

Secure enclave

Isolated, secure area of a processor for protecting sensitive data