Web Security Basics

Defense-in-depth is the architectural practice of layering redundant, independent defensive controls throughout every layer of an application. If an attacker successfully bypasses an outer defense (such as client-side input validation), inner defensive layers (such as parameterized database queries, strict Content Security Policies, and least-privilege database user permissions) prevent complete system compromise.

Developing cryptographic algorithms requires advanced mathematical proof and years of global cryptanalysis. In-house implementations inevitably suffer from subtle mathematical flaws, side-channel timing leaks, predictable pseudo-random seeds, and CPU instruction vulnerabilities. Engineers must always rely on peer-reviewed, industry-standard primitives (e.g., Argon2id, AES-256-GCM, Ed25519) implemented by audited libraries like libsodium or Node's native Web Crypto API.

No. HTTPS only provides transport layer encryption to prevent network eavesdropping and tampering between the client and server. It provides zero protection against application-layer vulnerabilities such as Broken Object Level Authorization (BOLA), parameter tampering, SQL injection, credential stuffing, or business logic flaws.

Authentication (AuthN) is the process of verifying WHO a user or entity is (e.g., verifying a password, TOTP token, or passkey signature). Authorization (AuthZ) is the process of determining WHAT an authenticated entity is permitted to access or execute (e.g., verifying whether User A has permission to read invoice #4820). Most security breaches in modern web apps occur at the authorization layer.

Continuous automated scanning should run weekly or on every deployment, combined with quarterly technical reviews and annual penetration testing.

Automated vulnerability checks and static analysis gates run in CI/CD pull requests, failing builds if critical severity issues are identified.