Cryptography and Security Terminology

Flashcards covering key concepts, terms, and definitions related to cryptography and security.

Double Transposition Cipher

Employs both Confusion and Diffusion principles in its design.

Caesar Cipher

A simple substitution cipher that shifts letters by a specified amount.

Security of a Cryptosystem

A cryptosystem is secure if the best-known attack requires as much work as an exhaustive key search.

Confidentiality

Prevents unauthorized access to information.

Integrity

Ensures data remains unchanged during storage or transmission.

XOR Operation

A binary operation that outputs true or '1' only when the inputs differ.

One-Time Pad

A provably secure cryptosystem that requires a key as long as the message.

Kerckhoffs' Principle

A cryptosystem should be secure even if the algorithm is public; only the key must remain secret.

Availability

Ensures that information and resources are accessible to authorized users when needed.

Additives in Codebook Ciphers

Used to obfuscate statistical information in the encrypted message.

Impracticality of One-Time Pad

The key length is the same as the message, making it impractical to transmit.

F Function in Cryptography

A function that typically applies an operation, such as XOR, between the right half of plaintext and a key.

Electronic Codebook (ECB) Mode

A block cipher mode that encrypts identical plaintext blocks into identical ciphertext blocks.

RC4

A type of stream cipher used in various encryption protocols.

Counter (CTR) Mode

A block cipher mode that allows a block cipher to act as a stream cipher.

Vulnerability of DES

DES is vulnerable due to its short key length of 56 bits.

Message Authentication Code (MAC)

Designed to protect the integrity of messages.

Symmetric Key Crypto Advantage

Symmetric Key Crypto is much faster than Public Key Crypto.

Diffie-Hellman Key Exchange

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

Non-repudiation

Assures that someone cannot deny the validity of their digital signature.

Public Key Crypto

Can achieve non-repudiation and allows for confidentiality in message transmission.

Digital Certificate

A document that binds the identity of an entity to a public key.

Value of x in mod arithmetic

To solve 5x mod 17 = 1, find a value of x that satisfies the equation.

Existence of Private Key

A private key does not exist in a digital certificate; only the public key is present.

RSA

An asymmetric cryptographic algorithm used in public key encryption.

SHA-256

A cryptographic hash function that produces a 256-bit hash.

Properties of Cryptographic Hash Functions

Include being easy to compute and infeasible to reverse.

Integrity of Messages

Can be protected using cryptographic hash functions combined with symmetric keys.

Probability in Hash Functions

The expected probability of hash collisions increases with the length of the output.

MD5 Usefulness

Can be used for detecting accidental error in data integrity.

Output Requirements in Hash Functions

A typical output should have a hash length double that of the key size in symmetric key crypto.

HMAC Verification

Alice sends h(M, K) to verify the integrity of message M.

Digital Signature of Hash Value

Provides an efficient way to ensure the integrity of large messages.

Avalanche Effect

A change to one bit of input should affect about half of the output bits.

Capabilities of Crypto Hash Functions

Include data corruption detection and message fingerprinting.

Fraud Rate in Biometric Recognition

Occurs when an unauthorized user is mistakenly authenticated.

Password Verification with Salts

Both the password hash and salt values are stored in the password file.

Lowest Equal Error Rates

The iris scan has the lowest equal error rates among biometric methods.

Web Cookies Storage

Stored on the user's machine.

Mutual Authentication Protocol

Involves the exchange of messages using a symmetric key and nonces.

Perfect Forward Secrecy

Ensures that the compromise of long-term keys does not compromise past session keys.

Nonce Usage

Nonces enhance security by providing freshness in responses.

Password Verification Method

Utilizes cryptographic hash functions to ensure security.

'Something You Are' Authentication

Biometric characteristics like fingerprints and iris scans.

Challenges in Network Authentication

Include observational attacks, replay attacks, and active attacks.

Authentication vs. Authorization

Authentication verifies identity, while authorization determines permissions.

Potential Security Threats in Protocols

Includes possible capture of passwords by attackers.

Two-Factor Authentication

Combines something you know (password) with something you have (identification code).