A
Access Control
Security mechanisms that regulate and restrict user or system access to resources based on predefined policies, ensuring only authorized entities can perform specific actions.
Access Control List (ACL)
A list of permissions attached to an object, specifying which users or systems can access the object and what operations they can perform.
Advanced Encryption Standard (AES)
A symmetric encryption algorithm established by NIST that uses fixed block sizes and key lengths of 128, 192, or 256 bits to encrypt data securely.
B
Bell Inequality
A concept demonstrating that certain predictions of quantum mechanics are incompatible with local hidden variable theories, validating quantum entanglement.
Bell-LaPadula Model
A security model that focuses on data confidentiality, enforcing rules that prevent unauthorized access by specifying no read up (Simple Security Property) and no write down (Star Property).
Biba Model
A security model focused on data integrity, ensuring that unauthorized users cannot modify data and enforcing rules like no write up and no read down.
C
Certificate Authority (CA)
An entity responsible for issuing and managing digital certificates, verifying the identity of entities, and ensuring secure communication in a public key infrastructure (PKI).
Cipher Block Chaining (CBC)
A block cipher mode of operation where each ciphertext block is XORed with the next plaintext block before encryption, enhancing security by introducing dependency between blocks.
Cryptographic Module
A hardware or software component that implements cryptographic algorithms and functions, ensuring secure key management and data protection.
D
Data Encryption Standard (DES)
A previously dominant symmetric-key algorithm for the encryption of digital data, now considered insecure and largely replaced by AES.
Decryption
The process of converting encrypted data (ciphertext) back into its original, readable format (plaintext) using a cryptographic key.
Digital Signature
A mathematical scheme for verifying the authenticity of digital messages or documents, providing non-repudiation and integrity.
E
Elliptic Curve Cryptography (ECC)
An approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields, offering smaller key sizes for equivalent security.
Encryption
The process of encoding information so that only authorized parties can access it, transforming plaintext into ciphertext.
Entanglement
A quantum physical phenomenon where particles interact in such a way that the quantum state of each particle cannot be described independently of the state of the others.
F
Fault Tolerance
The property that enables a system to continue operating properly in the event of the failure of one or more of its components.
Forward Secrecy
A feature of specific key agreement protocols that gives assurances that session keys will not be compromised even if long-term secrets used in the session key exchange are compromised.
FIPS 140-2/3
Federal Information Processing Standards that specify the security requirements for cryptographic modules used within computing environments.
G
Galois/Counter Mode (GCM)
A mode of operation for symmetric-key cryptographic block ciphers that provides both data authenticity (integrity) and confidentiality.
Grover's Algorithm
A quantum algorithm that finds with high probability the unique input to a black box function that produces a particular output value, speeding up unstructured searches.
Guaranteed Entropy
The mathematically provable lower bound of unpredictability in a random number sequence, a key feature of QRNGs.
H
Hash Function
Any function that can be used to map data of arbitrary size to fixed-size values, typically used in digital signatures and data integrity checks.
Hardware Security Module (HSM)
A physical computing device that safeguards and manages digital keys, performs encryption and decryption functions for digital signatures, and provides strong authentication.
Heisenberg Uncertainty Principle
A fundamental theory in quantum mechanics stating that it is impossible to measure two conjugate variables (like position and momentum) simultaneously with infinite precision.
I
Initialization Vector (IV)
A fixed-size input to a cryptographic primitive that is typically required to be random or pseudorandom, ensuring distinct ciphertexts for identical plaintexts.
Integrity
In information security, the assurance that data has not been altered or tampered with in an unauthorized manner.
Interference
A phenomenon in which two or more quantum waves superpose to form a resultant wave, heavily utilised in phase-diffusion QRNGs.
J
JSON Web Token (JWT)
An open standard that defines a compact and self-contained way for securely transmitting information between parties as a JSON object.
Jitter
The deviation from true periodicity of a presumably periodic signal, sometimes used as a source of entropy in classical random number generators.
Junction (Josephson)
A quantum mechanical device which is made of two superconducting electrodes separated by a barrier, used in superconducting quantum computing.
K
Key Encapsulation Mechanism (KEM)
A class of encryption techniques designed to secure symmetric cryptographic key material for transmission using asymmetric (public-key) algorithms.
Key Exchange
Any method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm.
Key Length
The size of a cryptographic key in bits. Longer keys generally provide stronger cryptographic security against brute-force attacks.
L
Lattice-based Cryptography
A class of post-quantum cryptographic algorithms whose security relies on the hardness of mathematical problems involving point lattices in high dimensions.
Local Oscillator
An electronic oscillator used to generate a signal, typically utilised in phase-diffusion QRNG systems to interfere with a quantum signal.
Logic Gate (Quantum)
A basic quantum circuit operating on a small number of qubits. They are the building blocks of quantum circuits, like classical logic gates.
M
Mac (Message Authentication Code)
A short piece of information used to authenticate a message and provide integrity and authenticity assurances on the message.
Man-in-the-Middle (MitM) Attack
An attack where the attacker secretly relays and possibly alters the communications between two parties who believe they are directly communicating with each other.
Monte Carlo Simulation
A broad class of computational algorithms that rely on repeated random sampling to obtain numerical results, heavily accelerated by Arquis RPUs.
N
NIST (National Institute of Standards and Technology)
A physical sciences laboratory and non-regulatory agency of the US Department of Commerce that establishes cryptographic standards and guidelines.
Non-repudiation
The assurance that someone cannot deny the validity of something. In cryptography, it ensures a sender cannot deny having sent a specific message.
Nonce
An arbitrary number that can be used just once in a cryptographic communication, often to prevent replay attacks.
O
One-Time Pad (OTP)
An encryption technique that cannot be cracked, requiring the use of a one-time pre-shared key the same size as, or longer than, the message being sent.
OpenSSL
A robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.
Out-of-Band Key Exchange
A method of securely distributing cryptographic keys through a channel completely independent of the one used for the encrypted data.
P
Perfect Secrecy
A concept in information theory meaning that the ciphertext reveals absolutely no information about the plaintext, achieved by the One-Time Pad.
Phase-Diffusion
A quantum optical effect where the phase of a laser becomes completely randomized, used as the foundational entropy source in Arquis QRNGs.
Post-Quantum Cryptography (PQC)
Cryptographic algorithms (usually public-key algorithms) that are thought to be secure against a cryptanalytic attack by a quantum computer.
Q
Quantum Key Distribution (QKD)
A secure communication method which implements a cryptographic protocol involving components of quantum mechanics to generate and share a secret key.
Quantum Random Number Generator (QRNG)
A device that utilises the inherent indeterminism of quantum mechanical phenomena to generate truly unpredictable random numbers.
Qubit
The basic unit of quantum information, the quantum version of the classical binary bit, capable of existing in a superposition of states.
R
Random Processing Unit (RPU)
A specialised hardware accelerator designed by Arquis to offload and accelerate randomness generation and processing for stochastic workloads.
Replay Attack
A form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed.
RSA
A widely used public-key cryptosystem for secure data transmission, relying on the practical difficulty of factoring the product of two large prime numbers.
S
Salt
Random data that is used as an additional input to a one-way function that hashes data, a password or passphrase, defending against dictionary attacks.
Shor's Algorithm
A quantum algorithm for integer factorization that can quickly crack widely used public-key cryptography schemes like RSA if run on a powerful enough quantum computer.
Superposition
A fundamental principle of quantum mechanics where a physical system exists partly in all its particular theoretically possible states simultaneously.
T
TLS (Transport Layer Security)
A cryptographic protocol designed to provide communications security over a computer network, widely used in web browsing and email.
True Random Number Generator (TRNG)
A device that generates random numbers from a physical process, rather than by means of an algorithm.
Two-Factor Authentication (2FA)
A security process in which users provide two different authentication factors to verify themselves, better protecting both the user's credentials and the resources.
U
Unconditionally Secure
A cryptographic system is unconditionally secure if it cannot be broken even with infinite computational power (e.g., One-Time Pad).
Unpredictability
In the context of RNGs, the inability for an adversary to guess the next generated number even with full knowledge of past outputs and system design.
User Authentication
The process of verifying the identity of a user who is attempting to access a system, network, or application.
V
Validation
The process of confirming that a cryptographic module, algorithm, or system meets specified security standards (e.g., FIPS validation).
Vector
An array of data elements or initialization values often utilised in block cipher modes of operation and stream ciphers.
Verification
The process of proving the authenticity of a digital signature or the integrity of a message.
W
Web of Trust
A decentralised trust model used in PGP (Pretty Good Privacy) where users verify and sign each other's public keys.
Whirlpool
A cryptographic hash function designed by Vincent Rijmen and Paulo S. L. M. Barreto, which produces a hash of 512 bits.
Whitening
A conditioning process applied to raw entropy streams to remove biases and ensure a uniform distribution of random bits.
X
X.509
An ITU-T standard defining the format of public key certificates, widely used in many Internet protocols, including TLS/SSL.
XOR (Exclusive OR)
A fundamental bitwise logical operation heavily used in cryptography because it is perfectly reversible; a bit XORed with the same key bit twice returns to its original state.
XSS (Cross-Site Scripting)
A type of security vulnerability typically found in web applications that enables attackers to inject client-side scripts into web pages viewed by other users.
Y
Yarrow
A cryptographic pseudorandom number generator algorithm designed by Bruce Schneier and John Kelsey, later succeeded by Fortuna.
Y-gate
A single-qubit quantum gate that represents a rotation around the Y-axis on the Bloch sphere, flipping both the computational basis states and adding a relative phase.
YubiKey
A hardware authentication device manufactured by Yubico that supports one-time passwords, public-key encryption and authentication.
Z
Zero-Knowledge Proof
A cryptographic method by which one party can prove to another party that they know a value, without conveying any information apart from the fact that they know the value.
Zeroization
The practice of securely erasing sensitive data, such as cryptographic keys, from electronic storage to prevent recovery by unauthorized entities.
Z-gate
A single-qubit quantum gate that acts as a phase shift, leaving the |0> state unchanged while mapping |1> to -|1>.