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Stream
What it is A stream is a continuous flow of data between two points. It can go one way (download a song) or both ways (a video call). In apps and on the web, streams move small chunks in order - like a line of tiny packets - so audio, video, or ...
Steganalysis
What it is Steganalysis is the art of finding secret data hidden inside normal-looking files - like a message tucked into a photo, song, or video. Unlike cryptography (which scrambles data), steganography tries to hide that data so nobody notices ...
Spyware
What it is Spyware is malware that secretly watches what you do and sends that info to someone else. It can log passwords and chats, read emails, grab screenshots, track browsing, and even record keystrokes. Some variants target phones to read texts, ...
Spoofing
What it is Spoofing is when someone pretends to be a trusted person or service by faking details like email sender, phone number, website address, or even a Wi-Fi name. The goal is to make you drop your guard and click, share a code, or send money. ...
Spam
What it is Spam is unwanted messages sent in bulk - usually emails, but also texts or comments. Most are ads you never asked for; some try to trick you into clicking links or opening files that lead to phishing or malware. Quick explainer and ...
Social Engineering
What it is Social engineering is tricking people into doing something they shouldn’t - like clicking a link, sharing a code, or paying a fake invoice. Instead of hacking computers, attackers hack trust with stories that feel urgent, helpful, or ...
Smishing
What it is Smishing is phishing over SMS. You get a text that looks urgent or official and it tries to make you tap a link or reply with info. The goal is the same as classic phishing: steal passwords, card numbers, or one-time codes. Basics and ...
Signature
What it is In security, a signature is a recognizable pattern that points to a known threat. It can be a byte sequence inside a file, a file hash, a telltale filename or path, or a behavior that always shows up with a specific malware family. ...
SIEM (Security Information and Event Management)
What it is A SIEM is a central alarm system for security. It collects logs and alerts from your apps, servers, firewalls, and cloud accounts, then puts them in one place so patterns are easier to spot. Two ideas power it: SEM (watches events live and ...
Shadow Password Files
What it is Shadow password files are special system files on Unix/Linux that store the password hashes (not the actual passwords) for user accounts. Public info about users lives in /etc/passwd, while the sensitive, hashed passwords are kept in ...
Shadow Copy
What it is Shadow copy is a built-in Windows feature that takes quick snapshots of files and folders. These snapshots capture how your data looked at a moment in time, so you can roll back to an earlier version if something goes wrong. Think of it ...
SQL Injection (SQLi)
What it is SQL Injection is a way attackers trick a website into running their database commands. Instead of treating a form field (like “username”) as plain text, a vulnerable site stuffs that text straight into a database query. If an attacker ...
SHA-1
What it is SHA-1 is a one-way math function that turns any input (a file, a message, a certificate) into a short fingerprint called a hash. The output is always 160 bits long, no matter how big the input is. It’s great for quick “did this change?” ...
Session Hijacking
What it is Session hijacking is when an attacker steals your “logged-in” state - the cookie or token that proves you’re you - and uses it to act as you without knowing your password. They might grab it over a weak or fake Wi-Fi, from a infected ...
Security Software
What it is Security software is a set of apps and services that protect your devices and data from hackers, malware, and mistakes. It covers tools like antivirus/anti-malware, firewalls, VPNs, email and web filters, intrusion detection/prevention, ...
SECaaS
What it is Security-as-a-Service (SECaaS) means you rent security tools from the cloud instead of installing and running everything yourself. A provider hosts the tech (firewalls, antivirus, web filters, identity/login tools, intrusion detection, ...
Screened Subnet Firewall
What it is A screened subnet (also called a DMZ) is a simple layout with three areas: the internet, a small “buffer” network for public stuff (DMZ), and your private home/office network (LAN). People on the internet can only reach the DMZ (like your ...
Scareware
What it is Scareware is fake security or system-cleaning software that tries to panic you into installing it. It throws alarming pop-ups (“Your PC is infected!”), runs bogus “scans” that always find problems, and demands payment or a download to fix ...
SAML (Security Assertion Markup Language)
What it is SAML is a standard that lets you use one login to access multiple websites and apps. You sign in once at an identity provider (like your company or school account), and that provider sends a signed “assertion” to other services proving who ...
Safe Mode
What it is Safe Mode is a special Windows startup that loads only the core drivers and services needed to boot. It skips most third-party apps, autostart items, and advanced graphics so you can troubleshoot crashes, remove stubborn software, or roll ...