Glossary

2FA

Two-Factor Authentication

A security process requiring two distinct forms of identification — typically a password and a code from a separate device.

AES

Advanced Encryption Standard

A symmetric block cipher used worldwide for encrypting sensitive data, with key sizes of 128, 192, or 256 bits.

Argon2

Argon2 Key Derivation Function

The winner of the Password Hashing Competition, designed to be memory-hard and resistant to GPU cracking attacks.

Certificate Pinning

TLS Certificate Pinning

A technique that associates a host with its expected certificate, preventing man-in-the-middle attacks with forged certificates.

Checksum

File Checksum

A value computed from file data used to verify that the file hasn't been altered or corrupted.

Clickjacking

UI Redress Attack

An attack that tricks users into clicking hidden elements by overlaying invisible frames on top of legitimate page content.

Command Injection

OS Command Injection

An attack passing arbitrary operating system commands through a vulnerable application to the host system.

CORS Misconfiguration

CORS Security Misconfiguration

Overly permissive CORS headers allowing unauthorized origins to read sensitive API responses in the browser.

CSRF

Cross-Site Request Forgery

An attack tricking an authenticated user into submitting unintended requests to a web application.

CVE

Common Vulnerabilities and Exposures

A standardized catalog of publicly known security vulnerabilities, each assigned a unique CVE-YYYY-NNNNN identifier.

DDoS

Distributed Denial of Service

An attack that overwhelms a server or network with traffic from many distributed sources, making it unavailable to legitimate users.

Defense in Depth

Defense in Depth Strategy

A security approach using multiple layers of protection so that if one layer fails, others still provide defense.

E2EE

End-to-End Encryption

A communication system where only the sender and recipient can read messages, with encryption keys never accessible to intermediary servers.

Entropy

Password Entropy

A measure of randomness or unpredictability in a password, expressed in bits, indicating resistance to guessing.

FIDO2

Fast Identity Online 2

An authentication standard enabling passwordless login through hardware security keys or biometrics using public key cryptography.

HMAC

Hash-based Message Authentication Code

A mechanism combining a cryptographic hash with a secret key to verify data integrity and authenticity.

HSTS

HTTP Strict Transport Security

An HTTP header instructing browsers to only connect via HTTPS, preventing protocol downgrade attacks.

Insecure Deserialization

A vulnerability where untrusted data is deserialized without validation, potentially enabling remote code execution.

Key Derivation

Key Derivation Function

A function that derives one or more secret keys from a password or passphrase using a pseudorandom function.

Nonce

Number Used Once

A random or sequential value used exactly once in cryptographic operations to prevent replay attacks and ensure message freshness.

OWASP Top 10

OWASP Top Ten Web Risks

A regularly updated list of the ten most critical web application security risks, published by the Open Web Application Security Project.

Password Hashing

Converting passwords into fixed-length hashes using algorithms like bcrypt or Argon2 for secure storage.

Path Traversal

Directory Traversal Attack

Exploiting insufficient input validation to access files outside the intended directory using ../ sequences.

Penetration Testing

Penetration Testing (Pentest)

Simulating real-world attacks against a system to identify security vulnerabilities before malicious actors do.

PGP

Pretty Good Privacy

An encryption program providing cryptographic privacy and authentication for data communication.

PKI

Public Key Infrastructure

A framework of certificate authorities, digital certificates, and key pairs that enables secure encrypted communication and identity verification.

Public Key

Public Key Cryptography

A cryptographic system using paired keys where the public key encrypts and only the private key can decrypt.

QR Code

Quick Response Code

A two-dimensional barcode that stores data (URLs, text, contact info) readable by cameras and scanners.

RBAC

Role-Based Access Control

An authorization model that assigns permissions to roles rather than individual users, simplifying access management at scale.

RSA

Rivest-Shamir-Adleman

An asymmetric cryptographic algorithm using public/private key pairs for encryption and digital signatures.

Salt

Cryptographic Salt

Random data added to a password before hashing to ensure identical passwords produce different hashes.

Sandbox

Security Sandbox

An isolated execution environment that restricts a program's access to system resources, limiting the impact of malicious code.

Sensitive Data Exposure

A vulnerability where applications fail to adequately protect sensitive data like passwords, tokens, or PII in transit or at rest.

SHA-256

Secure Hash Algorithm 256-bit

A cryptographic hash function producing a 256-bit digest, widely used for data integrity verification.

SQL Injection

SQL Injection Attack

Inserting malicious SQL code into application queries to access, modify, or delete database data.

SRI

Subresource Integrity

An HTML attribute providing a cryptographic hash to verify that fetched resources have not been tampered with.

SSL/TLS

Secure Sockets Layer / Transport Layer Security

Cryptographic protocols providing secure communication over networks, used for HTTPS.

SSRF

Server-Side Request Forgery

An attack making the server send requests to unintended internal or external resources on behalf of the attacker.

Steganography

Digital Steganography

The practice of hiding secret data within ordinary files (images, audio) without visible change.

Threat Modeling

Security Threat Modeling

A structured process for identifying potential threats, attack vectors, and mitigations during system design.

TOTP

Time-based One-Time Password

A temporary passcode generated from a shared secret and the current time, used in two-factor authentication.

WAF

Web Application Firewall

A security layer that filters HTTP traffic between a web application and the internet, blocking common attacks like SQL injection and XSS.

XSS

Cross-Site Scripting

An attack injecting malicious scripts into web pages viewed by other users, stealing data or session tokens.

XXE

XML External Entity Attack

An attack exploiting XML parsers to access local files, perform SSRF, or cause denial of service via entity expansion.

Zero-Day

Zero-Day Vulnerability

A software vulnerability unknown to the vendor and without a patch, actively exploited before a fix is available.