Glossary

Reset
  • 2FA
  • Account recovery
    The process of getting account access back after losing a password, phone, or second factor.
  • Adi Shamir
    One of the three authors of RSA and a major cryptographer.
  • AES
    A common standard algorithm for encrypting data. The acronym alone does not guarantee a secure product.
  • AI agent
    An AI system that does not only answer, but can use tools and perform steps.
  • Allowlist
    A list of explicitly allowed items, such as domains, applications or commands.
  • API key
    A secret string used by an application to authenticate to an API.
  • Audit log
    A record of important actions that helps determine what happened.
  • Authentication
    Identity verification. A service checks whether you really are who you claim to be.
  • Authenticator app
    A phone app that generates short one-time codes for safer login.
  • Authoritative DNS server
    A DNS server that holds the official answers for a specific domain.
  • Authorization
    The decision about what a logged-in user may see or do.
  • Backdoor
    A hidden or special access path into a system that bypasses normal protection.
  • Base64
    A way to write binary data as plain text.
  • Bash
    A common Unix shell used on Linux and servers.
  • Bernstein v. United States
    A court case about whether encryption source code can be protected as free speech.
  • Bruce Schneier
    A well-known security expert and author writing about cryptography, trust and system security.
  • Brute-force attack
    Automatically trying many combinations until one works.
  • CALEA
    A U.S. law requiring telecommunications infrastructure to support lawful interception.
  • Clipper Chip
    A U.S. proposal for an encryption chip with a mandatory path for government access to keys.
  • Command and control
    A communication channel through which an attacker controls a compromised system.
  • Command chaining
    Connecting multiple commands so the output or result of one affects the next.
  • Command line
    A text interface where commands are typed for the computer.
  • Cookie
    A small piece of data stored in the browser. A site can use it to remember login, settings, or a tracking identifier.
  • Credentials
    The information used to log in to a service, usually username, email, password, code, or security key.
  • Crypto Wars
    The long-running political and legal fight over whether strong encryption should be freely available or controlled by governments.
  • curl
    A command-line tool for downloading or sending data over the network.
  • Cypherpunks
    A community that promoted cryptography as a practical defense of privacy and freedom.
  • Daniel J. Bernstein
    A cryptographer and mathematician known in part for a lawsuit over cryptography export controls.
  • Data breach
    A situation where sensitive or non-public data reaches someone who should not have access.
  • David Chaum
    A cryptographer associated with anonymous communication, digital cash and blind signatures.
  • DES
    An older symmetric encryption standard that became central to debates about government influence on cryptography.
  • Device fingerprinting
    Combining technical details about a device and browser into an identifier that can distinguish you from others.
  • Dictionary attack
    Trying common words, known passwords, and previously leaked combinations instead of guessing everything randomly.
  • Diffie-Hellman key exchange
    A method that lets two parties agree on a shared secret over an insecure channel.
  • dig
    A command-line tool for querying DNS.
  • DNS
    The system that translates domain names into the technical addresses of servers.
  • DNS cache
    Temporarily stored DNS answers so they do not have to be requested again each time.
  • DNS exfiltration
    Moving data out of a system using DNS queries or responses.
  • DNS lookup
    A query where a computer asks DNS for information about a domain.
  • DNS over HTTPS
    A way to send DNS queries over encrypted HTTPS connections.
  • DNS over TLS
    A way to send DNS queries over encrypted TLS connections.
  • DNS record
    One entry in DNS that says something about a domain or subdomain.
  • DNS resolver
    A service or server that resolves DNS queries on behalf of the user.
  • DNS tunneling
    Abusing DNS to move data that does not belong in normal DNS queries.
  • DNSSEC
    A DNS extension that makes it possible to verify the authenticity of a DNS answer.
  • Domain name
    A human-readable name for an internet service, such as a website address.
  • Dropper
    A program that delivers or places additional malicious code on a system.
  • Egress filtering
    Limiting where a system is allowed to connect outward.
  • Electronic Frontier Foundation
    An organization defending digital rights, privacy and free expression.
  • Encrypted communication
    Communication protected by encryption so its content is not easily readable in transit.
  • Encryption
    Turning data into a form that cannot be understood without the right key.
  • End-to-end encryption
    Encryption where only the sender’s and recipient’s devices read the message, not the server in between.
  • Eric Hughes
    A cypherpunk and author of A Cypherpunk's Manifesto.
  • Escrowed Encryption Standard
    A standard associated with the Clipper Chip and the idea of mandatory key escrow.
  • Exploit
    A concrete method, procedure, or code that abuses a vulnerability.
  • Export controls on cryptography
    Rules that historically restricted the export of strong cryptography from a country.
  • FIPS
    A family of U.S. federal technical standards, including some cryptographic standards.
  • FIPS 46
    The standard that formally introduced DES in the United States.
  • Four Horsemen of the Infocalypse
    A rhetorical list of threats used as an argument for greater control over communication.
  • FQDN
    A fully qualified domain name including all parts of the domain.
  • Hardware security key
    A small physical key for safer login, often using USB, NFC, or Bluetooth.
  • Hardware wallet
    A physical device designed to store cryptocurrencies and secret keys more safely.
  • Human-in-the-loop
    A safety approach where important steps must be confirmed by a human.
  • IEEE
    An international technical organization known for standards, conferences and professional publications.
  • Indicator of compromise
    A clue that may indicate a system has been compromised.
  • Internet service provider
    The company you use to connect to the internet. It can see some network information about your traffic.
  • IP address
    A network address of a device or connection. Websites can use it to estimate your network or rough location.
  • John Gilmore
    A cypherpunk, programmer and co-founder of the Electronic Frontier Foundation.
  • Joseph Meyer
    A name associated with public criticism and expert debate around the DES standard.
  • Kerckhoffs’s principle
    The principle that encryption security should rely on the secrecy of the key, not the secrecy of the algorithm.
  • Key escrow
    A system where copies of encryption keys are held by a third party for possible later access.
  • Key recovery
    A way to regain an encryption key or access to data, often at the cost of additional risk.
  • Keylogger
    A tool that records keystrokes. It can steal passwords, messages, or other sensitive data.
  • Lawful access
    A policy term for giving the state access to protected communication or data under certain conditions.
  • Least privilege
    The rule that an account or tool should have only the permissions it really needs.
  • Leonard Adleman
    One of the three authors of the RSA algorithm.
  • Living off the land
    Using normal system tools for actions that may be malicious.
  • LLM
    A large language model that generates text and helps with tasks from instructions.
  • Loader
    Code that loads and runs another part of a program or attack.
  • Lost device
    A phone, laptop, or tablet you no longer control. The risk is not only local data, but also logged-in accounts.
  • Malware
    Malicious software that can spy, steal data, damage a device, or take control.
  • Martin Hellman
    A cryptographer known for work on public keys and Diffie-Hellman key exchange.
  • Message backup
    A copy of messages stored outside the active app, for example in the cloud or a file.
  • Metadata
    Data about communication or a file, not necessarily the content itself. For example time, sender, recipient, or location.
  • NIST
    A U.S. standards agency that publishes technical and security standards, among other work.
  • NSA
    A U.S. intelligence agency focused mainly on signals intelligence and communications.
  • nslookup
    An older but still used tool for DNS queries.
  • Obfuscation
    Deliberately making code or data harder to understand at first sight.
  • OPSEC
    Operational security: habits that reduce how much sensitive information you reveal about yourself and your plans.
  • Outbound network access
    Network connections that a system initiates outward.
  • OWASP Top 10
    A list of common and important web application risks, used as a map for security reviews.
  • Passphrase
    A longer password made from words or a sentence. It is often easier to remember and stronger than a short complicated password.
  • Password
    In general, a password is an arbitrary string of characters including letters, digits, or other symbols. If the permissible characters are constrained to be numeric, the corresponding secret is sometimes called a personal identification number (PIN).
  • Password manager
    An app that securely stores passwords and helps create a different strong password for every account.
  • Payload
    The part of an attack or program that carries the actual action or harmful content.
  • Payload staging
    A technique where a small first step is used to fetch or run the next part of an attack.
  • PGP / GPG
    Tools and standards for encrypting and signing emails or files.
  • Phil Zimmermann
    The creator of PGP, which brought strong encryption to ordinary users.
  • Phishing
    A fake message or page that looks trustworthy and tries to get your data or money.
  • Pipe
    A character or mechanism that passes the output of one command into another.
  • PowerShell
    A command environment and scripting language used mainly on Windows.
  • Privilege escalation
    A situation where a user or attacker gains higher permissions than they should have.
  • Prompt injection
    An attack on an AI app where user input makes the model ignore original rules or do unintended things.
  • Public Wi-Fi
    A shared wireless network in a café, hotel, train, or airport. You do not control who operates it.
  • Public-key cryptography
    Cryptography that uses a pair of keys: one public and one private.
  • Ralph Merkle
    A cryptographer associated with early public-key ideas and Merkle trees.
  • Ransomware
    A type of malware that locks or encrypts data and demands a ransom.
  • Recovery code
    A backup code used to get back into an account when you lose the usual second factor or phone.
  • Remote code execution
    A situation where someone can run their own code on a remote system.
  • Ron Rivest
    One of the three authors of the RSA algorithm.
  • Router
    A device that connects a home or company network to the internet.
  • RSA
    A well-known public-key cryptography algorithm named after Rivest, Shamir and Adleman.
  • Runtime code download
    A situation where a program downloads more code while it is running.
  • Sandbox
    An isolated environment where code can run with less impact on the rest of the system.
  • Secure messenger
    A messaging app designed with privacy in mind, usually with end-to-end encryption.
  • Security patch
    An update that fixes a security flaw or reduces the chance of abuse.
  • Session
    The period after login when a service remembers you as a logged-in user.
  • Session hijacking
    Abusing an active login so the attacker can act as the logged-in user.
  • Shell
    A program that accepts user commands and runs them on the system.
  • SIM swapping
    An attack where someone tries to move your phone number to a SIM card they control.
  • Skipjack
    The encryption algorithm used in the Clipper Chip proposal.
  • Social engineering
    Manipulating people so they take an action that helps the attacker.
  • Spear phishing
    Phishing prepared for a specific person or organization. It feels more believable because it uses real context.
  • SQL injection
    An attack on a web application where user input changes a database query.
  • Stager
    A small first program or command that prepares the next stage.
  • Strong cryptography
    Encryption that is practically unbreakable with available means when used correctly.
  • Subdomain
    A part of a domain placed before the main name, such as blog.example.com.
  • System prompt
    Hidden or higher-level instructions that define how an AI assistant should behave.
  • Third-party cookie
    A cookie set by an outside service embedded on the site you visit, such as an ad or analytics network.
  • Threat model
    A simple plan that says what you protect, from whom, and how an attack could happen.
  • Tim May
    A prominent figure in the cypherpunk movement and author of texts on crypto-anarchy.
  • Tool calling
    The ability of an AI system to use external tools, services or functions.
  • Tracking pixel
    An invisible or tiny element in a page or email that reports that the content was loaded.
  • TTL
    The time for which a DNS answer may be kept in cache.
  • TXT record
    A DNS record for text data, often used for verification or service configuration.
  • Vibe coding
    Building an application mainly with AI tools and quick prompts, often without deep review of the result.
  • VPN
    A service that routes your connection through another server and usually encrypts traffic between you and that server.
  • Vulnerability
    A weakness in an app, device, or configuration that can be abused for an attack.
  • Wassenaar Arrangement
    An international export control regime covering selected technologies, including some security tools.
  • Web application security review
    A practical review of a web app focused on common flaws, login, permissions, sessions, and data handling.
  • Whitfield Diffie
    A cryptographer associated with the birth of modern public-key cryptography.
  • Zero-day vulnerability
    A vulnerability abused before a widely available fix or defense exists.