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Find a tool, guide or study across all 67 pages.

Tool Subnet Calculator (IPv4 CIDR) Enter an IP and CIDR to instantly get the netmask, network, broadcast, host range and total number of addresses.
Tool IPv6 Subnet Calculator Get the network, address range, total count and compressed/expanded form of any IPv6 prefix.
Tool CIDR ↔ IP Range Converter Expand a CIDR to its address range, or collapse an IP range into minimal CIDR blocks.
Tool Base64 Encode / Decode Convert text to Base64 and back, with full Unicode (UTF-8) support.
Tool URL Encode / Decode Percent-encode text for safe use in URLs, or decode %xx sequences back.
Tool Hash Generator (MD5, SHA-1, SHA-256, SHA-512) Compute MD5, SHA-1, SHA-256, SHA-384 and SHA-512 digests from any text.
Tool JWT Decoder & Validator Decode a JWT's header and payload, inspect its claims, and verify an HS256 signature.
Tool JWT Generator (HS256) Create and sign a JSON Web Token (HS256/384/512) from a payload and secret.
Tool HMAC Generator (SHA-1, SHA-256, SHA-512) Compute an HMAC from a message and secret key using SHA-1/256/384/512, as hex or Base64.
Tool Hex ↔ Text Converter Convert text to hexadecimal and decode hex back to text, with UTF-8 support.
Tool Password Generator Create strong, random passwords with custom length and character sets — generated securely in your browser.
Tool Password Strength & Entropy Checker Measure a password's entropy in bits and estimate how long it would take to crack.
Tool API Key & Secret Generator Generate cryptographically secure API keys and secrets in hex, Base64url or alphanumeric.
Tool UUID Generator (v4 & v7) Generate random v4 UUIDs or time-ordered v7 UUIDs in bulk, ready to copy.
Tool Bcrypt Hash Generator & Checker Hash a password with bcrypt at an adjustable cost factor, or verify a password against a hash.
Tool Cron Expression Explainer Decode any cron schedule into plain English and preview the next run times.
Tool JSON Formatter & Validator Beautify, minify and validate JSON with clear error messages.
Tool YAML ↔ JSON Converter Convert YAML to JSON and back, with clear parse errors.
Tool Regex Tester Test regular expressions against text and inspect every match and group.
Tool .htaccess & nginx Redirect Generator Turn a list of old → new URLs into Apache .htaccess and nginx redirect rules.
Tool Data Breach Cost Estimator Estimate the financial impact of a data breach from records exposed and per-record cost.
Tool GDPR Fine Calculator Estimate the maximum GDPR penalty from annual turnover and infringement tier.
Tool Ransomware Downtime Cost Calculator Estimate the total impact of a ransomware attack from downtime, recovery and ransom.
Tool Security ROI (ROSI) Calculator Compute the return on a security investment from expected loss and mitigation effectiveness.
Tool Password Policy Generator Turn your password rules into a written policy plus Linux PAM and Windows config.
Tool Unix Timestamp Converter Convert Unix/epoch timestamps to human-readable dates and back — seconds or milliseconds.
Tool JSON ↔ CSV Converter Convert a JSON array of objects to CSV and back, with proper quoting and headers.
Tool Number Base Converter Convert between binary, octal, decimal and hexadecimal — with big-number support.
Tool .htpasswd Generator (bcrypt) Create a secure Apache/nginx basic-auth entry with a bcrypt-hashed password.
Guide What Is a Subnet? CIDR Notation Explained Subnets and CIDR notation explained in plain English — what /24 really means, how masks work, and how to divide a network without the headache.
Guide What Is a JWT and How Does It Work? How JSON Web Tokens really work — the header, payload and signature, what signing proves, and the security mistakes that bite teams.
Guide Bcrypt vs SHA-256: Why You Don't Hash Passwords with SHA SHA-256 is fast — which is exactly why it's the wrong way to store passwords. Here's why bcrypt (or Argon2) wins, and how salting and cost factors work.
Guide How to Create a Strong Password (and Why Length Wins) Forget swapping letters for symbols. Here's what really makes a password strong — entropy, length, uniqueness — and the simple system that beats memorising rules.
Guide What Is Base64 Encoding? (And Why It's Not Encryption) Base64 turns binary data into safe text — but it is not encryption. Here's how it works, why it grows your data by a third, and when to reach for it.
Guide HMAC Explained: How Webhook Signatures Work How HMAC proves a message came from who you think it did — the mechanism behind Stripe and GitHub webhook signatures, and how to verify them safely.
Guide Unix Timestamps Explained: Epoch, Seconds vs Milliseconds Epoch time, demystified: what the number really means, the seconds-vs-milliseconds bug that bites everyone, and why timestamps have no timezone.
Guide 301 vs 302 Redirects: Which to Use (and Why It Matters for SEO) 301 or 302? The wrong choice can quietly tank your SEO. Here's what each redirect means, when to use it, and the chain mistakes to avoid.
Guide IPv4 vs IPv6: What's the Difference? Why the internet is slowly moving from IPv4 to IPv6 — the address exhaustion problem, what actually changed, and how the two run side by side.
Guide MD5 vs SHA-1 vs SHA-256: Which Hash Should You Use? MD5 and SHA-1 are broken — but not for the reason most people think. Here's what each hash is for, why collisions matter, and which to actually use.
Guide Cron Syntax Cheat Sheet: How to Read Cron Expressions Stop guessing what a cron line does. A quick, practical reference to the five fields, the special characters, and the schedules you'll actually write.
Guide What Is a UUID? v4 vs v7 Explained What a UUID actually guarantees, why collisions are a non-issue, and why v7 is quietly replacing v4 for database keys.
Guide URL Encoding Explained (Percent-Encoding) Why spaces become %20 and ampersands become %26 — percent-encoding explained, plus the encodeURI vs encodeURIComponent decision that causes so many bugs.
Guide JSON vs YAML: When to Use Each JSON and YAML describe the same data in very different styles. Here's how they compare, the YAML traps to watch for, and which to reach for when.
Guide Regex Basics: A Beginner's Guide to Regular Expressions Regular expressions look like line noise until you learn the handful of building blocks. Here's the beginner's path, with examples you can test as you go.
Guide What Is HTTP Basic Authentication? The simplest way to password-protect a page — and its big caveat. How Basic Auth works, why HTTPS is mandatory, and where it fits.
Guide What Is an API Key? (And How to Keep It Secret) What an API key actually is, how it differs from a password or token, and the handful of habits that keep one from leaking into a breach headline.
Guide Hexadecimal Explained: Why Programmers Use Hex Why 0xFF beats 11111111: how hexadecimal works, its clean mapping to bytes, and where you'll meet it — colors, addresses, hashes and more.
Guide What Is GDPR? Fines and Compliance Basics GDPR in plain English: who it covers, the rights it grants, the two fine tiers (up to 4% of turnover), and where to start. Educational, not legal advice.
Guide What Is Ransomware? How Attacks Work and What They Cost How ransomware actually works, why the ransom is often the smallest cost, and the handful of defenses that make the biggest difference.
Guide What Is a Hash Function? What a hash function actually does, the properties that make it useful, and the difference between a cryptographic hash and a hash for storing passwords.
Guide What Is an IP Address? What an IP address is and how it routes your traffic — public vs private, static vs dynamic, and why your phone and your router don't share the same one.
Guide What Is Two-Factor Authentication (2FA)? Why a password alone isn't enough — how 2FA works, the difference between SMS codes, authenticator apps and hardware keys, and which to choose.
Guide Subnetting Cheat Sheet: CIDR, Masks & Host Counts A no-fluff subnetting reference: the CIDR-to-mask-to-hosts table, the powers-of-two shortcut, and the boundaries people always get wrong.
Guide Encoding vs Encryption vs Hashing: What's the Difference? Three words that get mixed up constantly — and confusing them causes real security bugs. Here's the clear distinction, with examples of each.
Guide What Is a Data Breach? Causes, Costs and Response What counts as a data breach, the causes behind most of them, why the true cost dwarfs the headline fine, and how to prepare before one happens.
Guide JWT vs Session Cookies: Which Auth Should You Use? Stateless tokens or server-side sessions? The real trade-offs between JWTs and session cookies — scalability, revocation, and the security gotchas of each.
Guide What Is a Salt in Password Hashing? Why two people with the same password should never have the same hash — what a salt is, how it stops rainbow tables, and how it differs from a pepper.
Guide What Is the CSV Format? Delimiters, Quoting & Pitfalls CSV looks trivial until a comma appears inside a value. Here's how the format really works — delimiters, quoting rules, and the gotchas that corrupt data.
Guide HMAC vs Digital Signatures: What's the Difference? Both prove a message wasn't tampered with — but only one proves who sent it to a third party. The difference between HMAC and digital signatures.
Guide How Binary Works: Binary Numbers Explained Why computers count in 1s and 0s, how to read a binary number, and how to convert to and from decimal — the foundation under bits, bytes and hex.
Guide Security ROI: How to Justify a Security Budget How to turn 'we should invest in security' into a number leadership respects — the ROSI model, with the inputs and pitfalls explained.
Guide What Is Credential Stuffing? (And How to Stop It) One breach, many break-ins: how attackers replay leaked passwords across every site — and why reuse, not weak passwords, is the real vulnerability.
Guide What Is a Password Manager? (And Why You Need One) You can't memorise a unique random password for 100 sites — and you shouldn't try. How password managers work, and why they're the single best security upgrade.
Research The Most Common Passwords of 2025 (and Why They Fail) '123456' still tops the list, 'admin' jumped to #2, and even P@ssw0rd-style passwords are cracked instantly. The 2025 most-common-passwords data, and what it teaches.
Research How Many CVEs Are Published Each Year? The Vulnerability Explosion Vulnerability disclosures hit a record 48,185 in 2025 — roughly 133 a day. The year-by-year numbers, why the curve is bending upward, and what it means for defenders.
Research IPv6 Adoption in 2026: The Year It Crossed 50% In March 2026, IPv6 quietly hit a milestone: for the first time, the majority of Google's traffic ran over IPv6. Here's what the data shows — and why sources disagree.
Research How Long Does It Take to Crack a Password? (2026 Data) A computed brute-force time table by password length and character set — showing exactly why length beats complexity. Transparent, reproducible model.