Security
Showing 11 articles
Webhook Signature Verification Failed: Causes and Fixes
Webhook signature verification failed? Usually it's the raw body, the digest encoding, or a missing timestamp prefix. Debug yours with a free HMAC tool.
Convert MD5 to SHA-256? Why It's Impossible (and What to Do Instead)
You can't convert an MD5 hash to SHA-256 — hashing is one-way. See what hash converter pages really do and the right fix for each task. Free online tools.
JWT Invalid Signature: Every Cause and How to Fix It
Your JWT says invalid signature. The real causes are cross-language key bytes, .env newlines and algorithm mismatch. How to pin down yours. Free decoder.
Linux File Permissions Explained: chmod 755, 644 & 777
Understand Linux file permissions: how chmod, octal (755, 644, 777) and rwx work, plus setuid, umask and safe defaults — with a free chmod calculator.
How TOTP Works: The Algorithm Behind 2FA Codes
How TOTP works, explained for developers: the RFC 6238 algorithm step by step, server-side verification, and what 2FA actually protects against.
JWT Security Best Practices: Attacks and Defenses (2026)
Secure your JWTs: stop alg:none and algorithm-confusion attacks, pin algorithms, rotate keys, validate claims, and store tokens safely. A 2026 developer guide.
How to Create an .htpasswd File (HTTP Basic Auth Guide)
Create an .htpasswd file with bcrypt or apr1, configure HTTP Basic Auth on Apache, nginx, Docker and Kubernetes, then lock it down. Hands-on 2026 guide.
bcrypt vs Argon2 vs scrypt: password hashing in 2026
Compare bcrypt, Argon2id, and scrypt against OWASP 2026 parameters, with a decision guide and code samples for picking a password hash.
How to Decode a JWT Token: Complete Guide for Developers
Learn how to decode a JWT token safely in the browser, Node.js, Python, and Go. Inspect header, payload, and claims with a free online JWT decoder.
Password Entropy: Calculate & Strengthen Your Passwords
Master password entropy: the formula, brute-force math, and why length beats complexity. Includes JS/Python code and a free generator.
Web Security Essentials: Hashing, Validation & Auth
Web security essentials: bcrypt vs Argon2 hashing, XSS and SQL injection prevention, JWT best practices, CSP headers and MFA — with JS code examples.