Cryptography

These flashcards cover fundamental concepts of cybersecurity and cryptography, including definitions of key terms, principles, and protocols.

Cryptography

The study of mathematical techniques to provide aspects of information security services.

Cryptanalysis

The study of mathematical techniques for attempting to defeat information security services.

Cryptology

The study of cryptography and cryptanalysis.

Plaintext

The original unencrypted message or information.

Ciphertext

The encrypted form of the plaintext message.

Encryption

The process of converting plaintext into ciphertext.

Decryption

The process of converting ciphertext back into plaintext.

Encryption Key

A key used to encrypt plaintext.

Decryption Key

A key used to decrypt ciphertext.

Alice

A common label for the sender in cryptographic protocols.

Bob

A common label for the receiver in cryptographic protocols.

Eve

A common label for an eavesdropper in cryptographic scenarios.

Mallory

A common label for a malicious attacker in cryptographic scenarios.

Confidentiality

A goal of cryptography that ensures data is not accessed by unauthorized parties.

Integrity

A goal of cryptography that ensures data has not been altered in unauthorized ways.

Authenticity

A goal of cryptography that ensures the source of the data is genuine.

Non-repudiation

A goal of cryptography that ensures authorship cannot be denied by the sender.

Pseudo-random number generation

The process of producing random numbers that are determinate from an initial value.

Anonymity

The state of being not identifiable within a set of subjects.

E-voting

An electronic method of casting votes in an election.

Secret sharing

A method of distributing a secret among a group so that only a specific subset can reconstruct it.

Zero-knowledge proof

A method used to prove that something is true without revealing any information about the proof.

Homomorphic encryption

Encryption that allows computation on ciphertexts, generating an encrypted result.

Chosen-plaintext attack

An attack model where the attacker can choose arbitrary plaintexts to be encrypted.

Chosen-ciphertext attack

An attack model where the attacker can choose ciphertexts and obtain the corresponding plaintexts.

Kerchhoff’s Principle

A principle stating that a cryptosystem should be secure even if everything except the key is public.

Shannon’s Maxim

The principle that the security of a cryptosystem should not rely on the obscurity of the algorithm.

Brute force

A method of defeating a cryptographic scheme by trying all possible keys.

Monoalphabetic substitution cipher

A cipher where each letter is replaced with another letter in a fixed substitution.

Frequency analysis

The study of the frequency of letters or groups of letters in a ciphertext.

Vigenère Cipher

A method of encrypting alphabetic text by using a simple form of polyalphabetic substitution.

Kasisky test

A method to determine the length of the keyword used in Vigenère cipher.

One Time Pad (OTP)

An encryption method that cannot be cracked if used correctly, utilizing a random key that is as long as the message.

Perfect Secrecy

A property of an encryption method where the ciphertext gives no information about the plaintext.

Symmetric Key Cryptography

Cryptography using the same key for both encryption and decryption.

Data Encryption Standard (DES)

A widely used symmetric-key algorithm for encrypting data.

Advanced Encryption Standard (AES)

A symmetric encryption algorithm that is the successor to DES, offering higher security.

Electronic Code Book (ECB)

A simple encryption mode where each block is encrypted independently.

Cipher Block Chaining (CBC)

An encryption mode that combines blocks to achieve confidentiality through chaining.

Certificate Authorities (CAs)

Entities that issue digital certificates for public key cryptography.

Transport Layer Security (TLS)

A protocol that ensures privacy between communicating applications and users on the Internet.

Public Key Cryptography

Cryptography employing pairs of keys: one public and one private.

Diffie-Hellman

A method for securely exchanging cryptographic keys over a public channel.

RSA

A widely used public key cryptography algorithm based on the factoring of large integers.

Digital Signatures

A mathematical scheme for verifying the authenticity and integrity of a message.

Cryptographic Hash Functions

Functions that convert input data into a fixed-size string of characters, which is typically a hash.

Collision resistance

The property of a hash function that makes it infeasible to find two different inputs that produce the same output.

X.509 Certificates

A standard format for public key certificates used in various network protocols.

Key Compromise

A situation in which a secret key is revealed to unauthorized parties.

Certificate Revocation List (CRL)

A list of certificates that have been revoked by the issuer.

Online Certificate Status Protocol (OCSP)

A protocol for checking the revocation status of a digital certificate.

Web of Trust

A decentralized model for establishing a chain of trust among users.

Pretty Good Privacy (PGP)

An encryption program that provides cryptographic privacy and authentication.

Gnu Privacy Guard (GPG)

A free implementation of the OpenPGP standard for encryption.

Transport Layer Security (TLS)

Ensures privacy between communicating applications and users on the Internet.

Key Signing

The process where trusted entities vouch for the authenticity of public keys.

Man-in-the-Middle (MitM) Attack

An attack where the attacker secretly relays and potentially alters the communication between two parties.

Authentication

The process of verifying the identity of a user or system.

Secret Sharing Schemes

Methods that allow a secret to be divided into parts, where some parts are required to reconstruct the secret.

Key Distribution Problem

The challenge of securely sharing cryptographic keys between parties.

Homomorphic Encryption

Encryption that allows computations to be carried out on ciphertexts.

Asymmetric Encryption

Encryption that uses a public key for encryption and a private key for decryption.

Compression

The process of reducing the size of data.

Nonce

A number used once in cryptographic communication to ensure security.

Pseudo-random Number

Numbers that approximate the properties of random numbers but are generated by a deterministic process.

Integrated Cryptographic System

Combination of various cryptographic techniques to enhance security.

Polygram Substitution Cipher

A substitution cipher that replaces groups of letters with other groups.

Quantum Key Distribution

A secure communication method that uses quantum mechanics to distribute encryption keys.

Keyed Hash Function

A hash function that uses a secret key for additional security.

Eavesdropping

Listening to or intercepting communication without the consent of the parties involved.

Block Cipher

An encryption method that transforms a fixed-size block of plaintext into a ciphertext block.