Symmetric Encryption

These flashcards cover key concepts and terminology related to symmetric encryption, its functionalities, and various types of attacks.

Symmetric Encryption

A type of encryption where the same key is used for both encrypting and decrypting data.

Block Cipher

An encryption method that processes data in fixed-size blocks.

Stream Cipher

An encryption method that encrypts data one bit or byte at a time.

Active Attack

An attempt to alter system resources or affect their operation.

Passive Attack

An attempt to learn or make use of information from a system without affecting system resources.

Man-in-the-Middle Attack

An attack where an attacker intercepts communication between two parties, capturing unencrypted data.

Plaintext

The original, unencrypted form of a message.

Ciphertext

The encrypted form of a message.

Key

A piece of information used to encrypt or decrypt a message.

Key Space

The set of all possible keys that can be used in encryption.

Caesar Cipher

A type of substitution cipher where each letter in the plaintext is shifted a certain number of places down or up the alphabet.

Frequency Analysis

A technique used to break ciphers by studying the frequency of letters or groups of letters in ciphertext.

Kerckhoff’s Principle

The principle that a cryptosystem should remain secure even if everything about the system is known, except for the key.

Security through Obscurity

The idea that a system is secure because its design or implementation is not known.

Confusion

A property of ciphers that makes it difficult to determine relationships between key bits and ciphertext bits.

Diffusion

A property of ciphers where a small change in plaintext results in a large change in ciphertext.

Enigma Machine

A cipher device used by the Germans during World War II, known for its complex encryption.

DES (Data Encryption Standard)

A symmetric-key algorithm for the encryption of digital data, now considered outdated.

AES (Advanced Encryption Standard)

A symmetric encryption standard that replaced DES, widely used and considered secure.

XOR Operation

A binary operation used in cryptography that outputs true or 1 only when one of its inputs is true.

Brute Force Attack

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

Asymmetric Encryption

A type of encryption where different keys are used for encrypting and decrypting data; one is public, and one is private.

Public Key

In asymmetric encryption, the key that can be freely distributed and is used to encrypt messages or verify digital signatures.

Private Key

In asymmetric encryption, the secret key that is kept by the owner and is used to decrypt messages or create digital signatures.

Cryptographic Hash Function

A mathematical algorithm that maps data of arbitrary size to a bit array of fixed size (a 'hash' or 'digest') designed to be a one-way function.

Digital Signature

A mathematical scheme for verifying the authenticity of digital messages or documents, often used to ensure integrity and non-repudiation.