OP_RETURN Attack Surface Demo
How Bitcoin's OP_RETURN creates a "public gallery" for arbitrary data, expanding the attack surface beyond simple blockchain storage.
🖼️
Gallery vs. Drawer
🔒
OP_RETURN hangs the image on the wall. Obfuscation stuffs it in a drawer.
The bytes exist in both cases, but exposure matters: one is sanctioned display, the other tolerated abuse.
🎯 OP_RETURN: Public Gallery
Sanctioned display. Standard RPC/REST APIs expose data URIs. Any HTTP client can fetch, parse, and render instantly. Universal content serving.
🗄️ Obfuscation: Hidden Drawer
Tolerated abuse. Data exists but requires specialized knowledge to find and extract. Higher barrier to access, lower attack surface.
✨ Self-Extracting Content
Data URI:
📋 Bitcoin RPC JSON Response
getrawtransaction <txid> true
⚠️ Why This Matters
-
Self-extracting by design: The
asmfield embeds a Data URI directly afterOP_RETURN. Any HTTP-capable client can fetch this JSON, parse the string, and set it as<img src="...">to render instantly. -
Zero specialized tooling: Just JSON + the web's standard
data:scheme. This makes content universally accessible to any browser, app, or script. - Expanded attack surface: Large OP_RETURN payloads + RPC/REST bridges = universal content serving. Unlike obfuscated data hidden in witness or P2SH scripts, OP_RETURN data is explicitly designed for retrieval and display.
- Liability difference: When node operators expose OP_RETURN via standard APIs, they become de facto content hosts—not just blockchain validators. The "public gallery" makes moderation impossible without protocol changes.
Note: This demo uses a benign SVG (orange background + Bitcoin symbol "₿").
Real transactions typically store hex bytes, but once converted to a Data URI,
any system that speaks HTTP can render it. The issue isn't what's stored—it's
how easily it's surfaced.