Applied Cryptography and PKI Flashcards

Plaintext

Original readable data.

Ciphertext

Encrypted, unreadable data.

Cipher

An algorithm used for encryption or decryption.

Key

A value used by a cryptographic algorithm.

Symmetric encryption

Encryption using one shared secret key.

Asymmetric encryption

Cryptography using public and private keys.

Hash

Fixed-length digest produced from input data.

Salt

Random data added before password hashing.

HMAC

A keyed hash used to verify integrity and authenticity.

Digital signature

A cryptographic proof of integrity and origin.

PKI

Infrastructure for managing public-key certificates and trust.

Certificate Authority

Trusted organization or system that issues certificates.

X.509

Common standard for digital certificates.

TLS

Protocol for protecting network communications.

Certificate chain

Linked sequence of certificates from a server certificate to a trusted root CA.

Session key

Temporary symmetric key used for a communication session.

Certificate revocation

Process of invalidating a certificate before expiration.

Perfect forward secrecy

Protection of past sessions if a long-term private key is later compromised.