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Security glossary

Plain-language answers to the security words you keep running into. Search, or browse by topic.

179 terms

#

  • "New number" family scamA message from an unknown number claims to be your child or relative with a new phone and asks you to pay something urgently.Scams
  • "Safe account" scamA caller posing as your bank or the police says your money is in danger and tells you to move it to a "safe account" they control.Scams
  • 3D Secure (card verification code)The extra step when you pay online: your bank sends you a code or asks you to approve in its app to confirm it is really you.Money

A

  • Account recoveryThe backup route back into an account when you forget the password or lose your phone: a recovery email, number or codes.Accounts
  • Account takeoverSomeone else gets into your account and uses it as if they were you, often locking you out in the process.Accounts
  • Active sessionsThe list of devices and browsers currently signed in to your account, which you can review and sign out of.Accounts
  • Advance-fee scamYou are promised a prize, loan, job or inheritance, but first have to pay a fee, tax or deposit that never ends.Scams
  • Advertising IDA number your phone gives apps so advertisers can recognise your device across apps without knowing your name.Privacy
  • AdwareUnwanted software that fills your screen or browser with ads, and sometimes tracks you or opens the door to worse programs.Malware
  • Antivirus (security software)A program that scans files and apps for known harmful software and blocks or removes it. It helps, but it is not a complete shield.Malware
  • App permissionsThe access you give an app to your contacts, camera, microphone, photos or location. Give only what the app clearly needs.Privacy
  • Approval-bombing (MFA fatigue)An attacker who has your password floods your phone with login approval requests, hoping you tap Approve just to make them stop.Accounts
  • Attack surfaceAll the places an attacker could try to get in: every account, app, device and connected service you have.Concepts
  • AuthenticationProving you are who you say you are, for example with a password, a code, a fingerprint or a passkey.Concepts
  • Authenticator appAn app on your phone that shows a short code which changes every half minute or so, used as the second step when you sign in.Accounts
  • AuthorizationDeciding what an account, person or app is allowed to do or see once it has been identified.Concepts

B

  • BackdoorA hidden way into a device or account that skips the normal login, left by malware or by a careless setup.Malware
  • BackupA second copy of what you cannot afford to lose, kept somewhere that a single accident cannot reach.Recovery
  • Backup codesA set of single-use codes you save when you turn on a second step, so you can still get in if you lose your phone.Accounts
  • Biometric unlockUnlocking a device or app with your fingerprint or face. It is convenient, but it still depends on a strong PIN as the fallback.Accounts
  • Blocking a cardAsking your bank to stop a card straight away so no further payments can be made with it, and to issue a new one.Recovery
  • Blocking a SIM cardAsking your operator to suspend the SIM of a lost or stolen phone so calls and SMS codes cannot reach whoever holds it.Recovery
  • BluetoothA short-range wireless link between devices such as headphones, cars and watches. Leave it on only when you use it, and pair only devices you recognise.Networks
  • BotA program that acts automatically, from harmless chat helpers to fake accounts and scripts that guess passwords at huge scale.Concepts
  • BotnetA large group of infected devices that an attacker controls remotely and uses together, usually without the owners knowing.Malware
  • Brute-force attackAn attacker's program tries huge numbers of passwords until one works. Long, unique passwords make this impractical.Accounts
  • Business email compromiseA fake email from a boss, supplier or colleague asks for an urgent payment or a change of bank account details.Scams

C

  • Caller ID spoofingMaking a call or text appear to come from a number you trust, such as your bank, by faking the number shown on your screen.Scams
  • Captive portal (Wi-Fi sign-in page)The page that opens when you join a hotel or cafe Wi-Fi and asks you to accept terms or sign in before you can go online.Networks
  • Card freeze (blocking a card)Stopping a lost, stolen or exposed card straight away, usually through the bank's app or phone line, so no further payments can pass.Money
  • Card skimmingA hidden device on an ATM or card reader that copies card data, often with a tiny camera to catch your PIN.Money
  • Cash on deliveryPaying the courier when the parcel arrives. It spares your card details, but still check what you are paying for.Money
  • Chargeback (card dispute)A request to your bank to reverse a card payment when goods never arrive, a charge is fraudulent or you did not authorise it.Recovery
  • Computer virusA program that attaches itself to other files and spreads when those files are opened or shared.Malware
  • ConsentYour free, informed agreement to let a company use your data in a specific way. You should be able to say no and to withdraw it later.Privacy
  • Contactless paymentPaying by holding a card or phone near the terminal. It is quick, and usually safe, because limits and checks still apply.Money
  • CookieA small file a website stores in your browser to remember you, for example that you are logged in, or to track you across sites.Privacy
  • Cracked softwarePaid software or games with the licence check removed. These files are one of the most common ways malware reaches computers.Malware
  • Credential stuffingAttackers take email and password pairs leaked from one site and automatically try them on many others.Accounts
  • Cryptocurrency walletAn app or device that holds the keys to your cryptocurrency. Whoever has the keys controls the coins, and transfers cannot be undone.Money
  • CryptojackingMalware that secretly uses your device's power to mine cryptocurrency for someone else, slowing it down and wearing it out.Malware
  • CVV (card security code)The 3 or 4 digit code on your card used to confirm card-not-present payments. It must stay private.Money
  • Cyber hygieneThe small routine habits, like updating, backing up and checking before clicking, that keep your digital life in good shape.Concepts
  • CybersecurityProtecting your accounts, devices and information from being accessed, stolen, damaged or locked by someone who should not have them.Concepts

D

  • Data breachWhen a company's or service's data is accessed or taken by people who should not have it, often including customer emails and passwords.Concepts
  • Data brokerA company that collects personal data from many sources, builds profiles and sells or shares them with others.Privacy
  • Data minimisationThe habit of sharing and keeping only the data that is really needed, because data that is not collected cannot leak.Privacy
  • Data request to a companyA written request asking a company what personal data it holds about you, or to correct or delete it.Privacy
  • Deepfake scamFake voice or video made with software to look and sound like someone you know, used to ask for money or secrets.Scams
  • Defence in depth (layered security)Using several protections together, so that when one fails another still stands between an attacker and you.Concepts
  • Digital footprintEverything about you that exists online: what you post, what others post about you, and what sites and apps quietly collect.Privacy
  • Digital signatureA way to prove that a message or file really came from a given sender and was not changed on the way.Concepts
  • DNS (the internet's address book)The system that turns a site name like example.com into the number address of its server. Whoever runs your DNS sees which sites you look up.Networks
  • DoxxingPublishing someone's private details, such as address, phone number or workplace, online to harass, scare or expose them.Privacy
  • Drive-by downloadMalware that installs itself just because you visited a booby-trapped page, using a flaw in an outdated browser or system.Malware

E

  • Encrypted DNS (private DNS)A DNS setting that encrypts your site lookups so others on the network cannot read or change them. It does not hide the site from your DNS provider.Networks
  • EncryptionScrambling information so that only someone with the right key can read it, even if the data is stolen or intercepted.Concepts
  • End-of-life softwareSoftware or devices whose maker no longer provides updates, so new security flaws stay open for good.Concepts
  • Escrow (protected payment)A system where a trusted third party holds the money until the buyer confirms the goods arrived as described.Money
  • Evil twin (fake hotspot)A Wi-Fi network set up by an attacker with the same or a similar name as a real one, to catch people who join it.Networks

F

  • Factory resetReturning a phone or computer to its original state by erasing everything on it. It is a strong way to remove a hidden problem.Recovery
  • Fake courier scamA message about a failed delivery, or a fake "courier" for your sale, that sends you to a page collecting your card details.Scams
  • Fake giveawayA post or message says you won a prize or can claim a free gift, but you must share a link, pay a fee or enter your details.Scams
  • Fake online shopA shop that copies real products and prices far below the market to take payments and then never deliver, or to steal card data.Scams
  • Fake receipt scamA buyer sends a screenshot of a bank receipt as proof of payment, but no money has actually reached your account.Scams
  • Find my deviceA built-in service from Apple or Google that shows a lost phone on a map and lets you lock it or erase it from afar.Recovery
  • FirewallA filter that decides which connections may enter or leave your device or network, blocking the ones nobody asked for.Malware
  • Firmware (device software)The built-in software that runs a device such as a router or camera. Updates to it close security holes that attackers look for.Networks

G

  • Guest networkA separate Wi-Fi network on your router for visitors and smart devices, kept apart from your own computers and phones.Networks

H

  • HackerSomeone who finds ways into systems. Some are criminals; others test security with permission to help fix problems.Concepts
  • HashingA one-way scramble that turns a password into a fixed code, so a service can check it without keeping the real password.Concepts
  • HTTPS (the padlock)The secure version of a web address. It encrypts what you send to the site, but does not prove the site itself is honest.Networks

I

  • IBANThe account number used to receive bank transfers. To get paid you only need to give this, never card details.Money
  • Identity theftSomeone uses your personal details, such as your ID number or documents, to open accounts, take credit or act as you.Recovery
  • Incident responseWhat you do, in order, when something goes wrong: stop the damage, secure your accounts, tell the right people and learn from it.Concepts
  • InfostealerMalware that collects saved passwords, cookies, card details and crypto wallets from your device and sends them away.Malware
  • Instant transfer (FAST, EFT, wire)A bank transfer that arrives within seconds, at any hour. It is convenient, and very hard to take back.Money
  • Investment scamA fake trading or crypto platform shows big profits on screen to make you deposit more, then blocks your withdrawals.Scams
  • IP addressThe number address your connection uses on the internet. Sites see it, and it shows your provider and roughly your area.Networks
  • Irreversible paymentA payment that is very hard or impossible to reverse once sent: bank transfers to strangers, gift cards, cryptocurrency, cash.Money

İ

K

  • KeyloggerA program, or sometimes a small device, that records every key you press, including passwords and card numbers.Malware
  • KVKK (Turkish data protection law)Türkiye's personal data protection law (No. 6698). It sets rules for how your data is handled and gives you rights over it.Privacy

L

  • Least privilegeGive a person, app or account only the access it needs for its job and nothing more.Concepts
  • Linked devicesThe list of phones, computers and browsers that are signed in to your account, for example in a messaging app.Recovery
  • Location sharingLetting an app, a person or a post reveal where you are, either live or as a place tag on what you share.Privacy
  • Login alertA message from a service telling you that your account was signed in to from a new device or place.Accounts
  • Login alertsNotifications from a service when your account is used from a new device or place, which help you notice a takeover early.Recovery

M

  • MAC addressA hardware identifier your device shows to Wi-Fi networks. Many phones can use a changing private address so you are harder to follow between places.Networks
  • Malicious browser extensionA browser add-on that can read the pages you visit and what you type, and sometimes turns harmful after an update or sale.Malware
  • MalvertisingAn advert, often on a normal site or in search results, that leads to a fake page or spreads malware.Malware
  • Malware (harmful software)Any program made to harm you or spy on you: steal passwords, lock your files, watch your screen or use your device without your knowledge.Malware
  • Man-in-the-middle attackAn attack in which someone secretly sits between you and a website or app, reading or changing what passes between you.Networks
  • Marketplace scamA fake buyer or seller on a second-hand or classified site who pushes you to pay or be paid outside the platform's protection.Scams
  • Metadata (photo and file details)Hidden details stored inside files, such as when and where a photo was taken, which device made it, or who wrote a document.Privacy
  • Mobile banking app securityUsing your bank's official app safely: a strong screen lock, device updates, notifications on, and never giving codes to anyone.Money
  • Mobile hotspot (tethering)Sharing your phone's mobile data as a Wi-Fi network for your laptop or tablet. A safer option than public Wi-Fi when set up with a strong password.Networks
  • Mobile walletAn app that keeps a digital version of your card on your phone and pays with it, without showing your real card number.Money
  • Money muleSomeone who lets their bank account be used to move money for others. People are often tricked into it by a "job" offer.Scams

N

  • Network name (SSID)The name your Wi-Fi shows in the list of networks. Anyone can make a network with the same name, so a familiar name proves nothing.Networks

O

  • One-time code (OTP)A short code sent or generated for one login or payment. Nobody who works for a real service will ever ask you to read it out.Accounts
  • Online task scamAn "easy job" such as liking videos or rating products pays a little at first, then asks you to top up an account to continue.Scams
  • Overpayment scamA "buyer" pays too much and asks you to send the difference back, but the original payment is fake or later reversed.Money
  • OversharingPosting more personal detail than is safe, such as your location, routine, children or documents, where many people can see it.Privacy

P

  • PasskeyA way to sign in with your fingerprint, face or device PIN instead of a password. It cannot be typed into a fake site.Accounts
  • PassphraseA password made of several random words, long enough to be strong yet easier to remember than a jumble of symbols.Accounts
  • PasswordA secret you type to prove an account is yours. The longer and more unique it is, the harder it is to guess or reuse against you.Accounts
  • Password managerAn app that creates, stores and fills in a different strong password for each account, protected by one master passphrase.Accounts
  • Password resetSetting a new password through the service's official reset process, usually with a link or code sent to your email or phone.Recovery
  • Password reuseUsing the same or a slightly changed password on several accounts, so one leak puts all of them at risk.Accounts
  • People-search siteA website that lets anyone look up a person's address, phone number, relatives and other details, often collected from public records.Privacy
  • Personal dataAny information that identifies you or can be traced back to you, such as your name, phone number, address, photo or ID number.Privacy
  • Personal emergency planA short, written list of what to do first if you lose a phone, get hacked or fall for a scam, prepared before it happens.Recovery
  • PhishingA fake message that pretends to be someone you trust so that you hand over a password, a code or money.Scams
  • Port forwardingA router setting that lets the outside internet reach a device inside your home network. Open only what you really need.Networks
  • Preserving evidenceSaving screenshots, messages, links, receipts and dates about a scam or attack before they disappear, so you can report it.Recovery
  • Privacy settingsThe options in an app or account that control who can see your posts, find you and use your data.Privacy
  • Private browsing (incognito mode)A browser mode that does not save your history or cookies on that device afterwards. It does not hide you from websites, your employer or your provider.Privacy
  • Public Wi-FiA shared network in a cafe, hotel, airport or mall. Anyone can join it, so you cannot know who else is on it or who runs it.Networks

Q

  • Quishing (QR code phishing)A fake QR code, often a sticker over a real one, that sends you to a page built to steal logins or payments.Scams

R

  • RansomwareMalware that locks or encrypts your files and demands payment to give them back.Malware
  • Recovery codes (backup codes)One-time codes a service gives you in advance so you can still log in if you lose your phone or authenticator app.Recovery
  • Recovery email and phone numberThe second email address or phone number on an account that the service uses to confirm it is you when you cannot log in.Recovery
  • Refund scamA message or call offering a refund, a rebate or compensation, used to get your card details, codes or remote access.Money
  • Remote access trojan (RAT)Malware, or a misused remote-control app, that lets someone else see and operate your device as if they were holding it.Malware
  • Remote wipeErasing a lost or stolen phone or laptop from a distance, so the data on it cannot be read by whoever holds it.Recovery
  • Rental scamA fake listing for a flat, holiday home or car, cheaper than similar ones, asking for a deposit before you can see it.Scams
  • Reporting fraudTelling your bank, the platform involved and the authorities about a scam, which can stop losses and help others.Recovery
  • Restoring from a backupBringing back your files, photos or phone data from a saved copy after a loss, a failure or an attack.Recovery
  • Revoking app accessRemoving the permission that an app or website was given to use your account, for example after "Sign in with Google".Recovery
  • Right to erasureYour right, in the cases the law allows, to ask a company to delete or destroy the personal data it holds about you.Privacy
  • RiskHow likely something bad is to happen and how much it would hurt. Good security spends effort where both are high.Concepts
  • Romance scamSomeone you met online builds a close relationship over weeks, then asks for money for an emergency, a trip or an investment.Scams
  • RootkitMalware that buries itself deep in the system so that it hides from the user and from many security programs.Malware
  • Router (modem)The box at home that connects your devices to the internet and creates your Wi-Fi. Its settings decide where all your traffic goes.Networks

S

  • SandboxA walled-off space where a program runs with limited access, so if it is harmful it cannot easily touch the rest of your device.Concepts
  • Saved card (card on file)Card details a shop, app or browser remembers for one-tap payments. Handy, but a breach or a hijacked account can expose them.Money
  • Scareware (fake virus alert)A pop-up or page claiming your device is infected, built to scare you into installing something or calling a number.Malware
  • Security certificateA digital document that lets a site prove who it is to your browser. A certificate warning means that proof failed.Networks
  • Security checkupA regular review of your key accounts: passwords, second step, recovery details, devices and connected apps.Recovery
  • Security keyA small physical device you plug in or tap to approve a login, giving very strong protection against fake sign-in pages.Accounts
  • Security questionsQuestions like "your first school" used to reset a password. The honest answers are often easy for others to find.Accounts
  • Security update (patch)A software update that fixes a security flaw. Installing it promptly closes the door attackers would otherwise try.Concepts
  • Seed phrase (recovery phrase)The 12 or 24 words that restore a crypto wallet. Anyone who has them owns your coins, so they are never shared or typed into a site.Money
  • SextortionSomeone threatens to share private images or claims to have them, unless you pay. It is a pressure tactic, and you are not to blame.Scams
  • Shared accountOne account used by several people. Share it with the service's own sharing feature rather than by passing the password around.Accounts
  • Sideloading (APK and unknown sources)Installing an app from a file or website instead of the official store, which skips the store's checks.Malware
  • Sign in with Google/Apple (single sign-on)Using one existing account, such as Google or Apple, to sign in to other sites instead of making a new password for each.Accounts
  • Signing out of all devicesEnding every active login of an account on every phone and computer, so an intruder who is still signed in is removed.Recovery
  • SIM PINA short code that locks your SIM card, so a thief who puts it in another phone cannot use your number.Recovery
  • SIM swapAn attacker gets your phone number moved to a SIM they hold, so your calls and SMS codes reach them instead of you.Scams
  • Smishing (SMS phishing)A scam text message that tries to make you tap a link or hand over a code, card number or password.Scams
  • Social engineeringTricking people, not computers: using trust, urgency or fear to get someone to hand over a code, a password or money.Concepts
  • Spear phishingA phishing message written for one person or company, using real details about them to look believable.Scams
  • Spending limit and online-use settingsSettings in your bank app that cap payments or turn online and foreign use on and off, so a leaked card can do less harm.Money
  • SpywareSoftware that secretly watches what you do and sends it to someone else: messages, location, passwords, browsing.Malware
  • StalkerwareAn app installed on someone's phone, usually by a person close to them, to secretly follow their messages, calls and location.Malware
  • Subscription trapA "free trial" or tiny first payment that quietly turns into a recurring charge you may not notice for months.Scams

T

  • Targeted advertisingAds chosen for you based on what you searched, visited, bought or where you go, collected across sites and apps.Privacy
  • Tech support scamA pop-up or caller claims your device is infected and asks you to install a remote-access app or pay for a fix.Scams
  • Third-party app accessApps and sites you have allowed to reach part of your account, such as your email or contacts, without knowing your password.Accounts
  • Threat modelAsking who might want to harm you, what they want, and what you most need to protect, so you spend effort where it counts.Concepts
  • TrackerA small piece of code in a website or app that records what you do and sends it to other companies, mostly for advertising.Privacy
  • Transaction alertA notification from your bank each time money leaves your account or card, so you see misuse within seconds.Money
  • Trojan (Trojan horse)Harmful software disguised as something useful or free, such as a game, a crack or an invoice, that you install yourself.Malware
  • Trusted deviceA device a service remembers so it asks for fewer checks. Fine for your own phone, a bad idea on a shared or public computer.Accounts
  • Two-factor authentication (2FA)A second proof, such as a code or a tap on your phone, required after your password so a stolen password alone is not enough.Accounts

U

  • Unauthorised transactionA payment or transfer you did not make or agree to. Reporting it quickly to your bank is the step that protects you most.Money

V

  • Verification code scamSomeone asks you to send a code you just received by SMS, usually pretending to be a friend or a company, to take over your account.Scams
  • Virtual cardA card number that exists only online, often with its own low limit, so a leak cannot reach your main account.Money
  • Vishing (voice phishing)A phone call from someone posing as a bank, police officer or official, pushing you to share codes or move money.Scams
  • VPN (virtual private network)A service that sends your traffic through an encrypted tunnel to the VPN company, hiding it from the local network and your internet provider.Networks
  • VulnerabilityA weakness or mistake in software or a system that an attacker can use to get in or cause harm.Concepts

W

  • Warning your contactsTelling friends, family and colleagues, by a normal call, that your account was hijacked so they do not fall for messages sent in your name.Recovery
  • Wi-FiThe wireless network that connects your phone and computer to the internet through a router, using radio signals instead of a cable.Networks
  • Wi-Fi encryption (WPA2, WPA3)The way your router scrambles Wi-Fi traffic so people nearby cannot read it. WPA2 or WPA3 is the right choice; WEP and open networks are not.Networks
  • WormMalware that spreads by itself from device to device over a network or by messages, without anyone opening a file.Malware
  • WPS (Wi-Fi Protected Setup)A shortcut that lets a device join Wi-Fi with a button or short PIN. The PIN method has known weaknesses, so it is best turned off.Networks

Z

  • Zero-dayA security flaw that attackers use before the maker knows about it or has released a fix.Concepts