9781260464009-Chapter-16-Cryptographic-Concepts

Cryptography

The science and art of encrypting information, ensuring its confidentiality, authenticity, and integrity during transmission and storage.

Cipher

A systematic method for transforming readable information into an unreadable format, allowing secure communication. The term originates from the Arabic word 'sifr,' which signifies empty or zero.

Plaintext

The original and unencrypted text or data that is easily readable; it is the input for encryption algorithms to generate ciphertext.

Ciphertext

The encrypted output resulting from applying an encryption algorithm to plaintext, rendering it unreadable without the proper decryption method.

Digital Signature

A cryptographic mechanism that uses public key cryptography to authenticate the origin of a digital message, ensuring that it has not been altered.

Key Length

The size of cryptographic keys, usually measured in bits, which directly affects the security level of encryption; longer keys generally provide stronger security.

Symmetric Encryption

A method of encryption where the same secret key is used for both encrypting and decrypting messages, requiring a secure way to share the key.

Asymmetric Encryption

A cryptographic system that employs a pair of keys: a public key used for encryption and a private key used for decryption, enhancing security for key distribution.

Hash Function

A computational algorithm that converts input data of any size into a fixed-size string of characters, typically used to ensure data integrity and security.

Key Exchange

The method by which cryptographic keys are securely shared between parties, enabling encrypted communication without the risk of interception.

Perfect Forward Secrecy

A cryptographic principle guaranteeing that session keys are not compromised even if the long-term private key is eventually breached, enhancing privacy.

Quantum Cryptography

The application of quantum mechanics principles to create secure communication channels, relying on quantum phenomena to ensure information privacy.

Lightweight Cryptography

Cryptographic schemes designed to operate effectively in environments with limited resources, such as IoT devices, by minimizing processing and memory usage.

Steganography

The method of concealing a message within another medium (e.g., embedding data within images), thus making the presence of the message undetectable.

Nonce

A unique number or value used only once in a cryptographic session to prevent replay attacks by ensuring freshness and uniqueness in transactions.

Entropy

A measure of randomness and unpredictability in cryptographic keys or systems, with higher entropy indicating stronger security against attacks.

Homomorphic Encryption

An advanced encryption technique that permits computations to be performed on ciphertext without revealing the underlying plaintext, preserving privacy.

Blockchain

A decentralized ledger technology that records transactions in a secure, immutable manner across a network of computers, ensuring transparency and resistance to tampering.

Elliptic Curve Cryptography (ECC)

A form of public key cryptography based on the properties of elliptic curves, allowing for smaller keys compared to other systems while maintaining equal security levels.

Key Stretching

A technique that reinforces weak cryptographic keys by applying additional computational efforts, thereby increasing the resistance to brute-force attacks.

Authenticated Encryption with Associated Data (AEAD)

An encryption scheme that simultaneously provides confidentiality for the data and integrity checks for associated data, ensuring both aspects are secure.

Counter Mode (CTM)

An encryption method that transforms a block cipher into a stream cipher by encrypting a sequential counter value and combining it with the plaintext.

Cipher Block Chaining (CBC)

An encryption mode that links the encryption of blocks such that each plaintext block is combined with the previous ciphertext block to enhance security.

Stream Ciphers

Encryption algorithms designed to encrypt data bit by bit or byte by byte, making them ideal for real-time applications requiring minimal latency.

Block Ciphers

Cryptographic algorithms used to encrypt data in fixed-size blocks, forming the basis of many encryption standards for secure communications.

Nonrepudiation

A critical principle in cryptography that ensures that a sender cannot deny sending a message, thus providing proof of the origin and integrity of transmitted data.