Add ECB Penguin to Playgrounds

[h4x0r]

What

Adds ECB Penguin to the Playgrounds section.

Why it's awesome

ECB Penguin is a free, interactive, zero-dependency web demo that visually demonstrates why AES-ECB mode is insecure:

• Encrypts Linux Tux with AES-ECB vs AES-GCM side by side — the penguin silhouette is preserved in ECB
• Decrypt with correct/wrong keys — ECB silently fails, GCM detects tampering
• Bit-flip attack demo — flip a ciphertext block and see ECB corrupt one block vs GCM refusing entirely
• Block heatmap overlay showing duplicate ciphertext blocks
• Interactive educational panels: block anatomy, key derivation, ECB vs GCM data flow
• Timeline of real-world attacks (BEAST, Lucky13, POODLE, GoldenDoodle) and why TLS 1.3 mandates GCM

Built with pure WebCrypto API — no dependencies, runs entirely in the browser.

Source: https://github.com/SecurityRonin/ecb-penguin