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WebCrypt MCP Server

io.github.putervision/webcrypt · 15 stars · JavaScript · MIT

MCP server Zero-dependency Web Crypto & AI Agent MCP Server (AES-256-GCM, RSA-4096, PQC, Signatures).

Install

The repo has no one-line install. Follow its README.

Published as

  • npmwebcryptstdio

From the server's entry in the official MCP Registry.

Open the repo

Files

README.md

WebCrypt v1.0.1

Zero-dependency Web Crypto & native AI Agent Tooling (MCP) for modern JavaScript.

npm version npm downloads Node TypeScript MCP Tests Coverage PuterVision Triad License: MIT

AES-256-GCM symmetric encryption, RSA-4096 hybrid public keys, ECDH key agreement, ECDSA/HMAC digital signatures, and Post-Quantum KEM (Kyber/Dilithium) — zero runtime dependencies, pure Web Crypto API.


⚡ Quickstart (15 Seconds)

1. Installation

# 📦 Install as project library (Node.js, TypeScript, Browser)
npm install webcrypt

# 🌐 Install globally (CLI utilities & global MCP tools)
npm install -g webcrypt
import { WebCrypt, WebCryptAsym } from "webcrypt";

// 🔒 Symmetric AES-256-GCM (600k PBKDF2 iterations)
const wc = new WebCrypt();
const encrypted = await wc.encryptText("Secret payload", "password");
const decrypted = await wc.decryptText(encrypted, "password");

// 🔑 Asymmetric RSA-4096 Hybrid Encryption
const wca = new WebCryptAsym();
const keyPair = await wca.generateKeyPair(4096);
const cipher = await wca.encryptText("Secret payload", keyPair.publicKey);
const plain = await wca.decryptText(cipher, keyPair.privateKey);

2. Auto-Setup for AI Agents & IDEs (MCP Server)

# Initialize MCP server, agent skills, and rules across your project
npx webcrypt init  # or `webcrypt init` if installed globally

Supports Google Antigravity, Cursor, Claude Desktop, VS Code / Copilot, Windsurf, Cline, and Zed.


🤖 Why AI Agents Need WebCrypt MCP

Equip autonomous coding agents with an authenticated cryptographic vault directly in their toolbelt:

  • 🔐 Confidential Local Vaulting (encrypt_payload): Encrypt API keys and state memory before writing to disk to prevent prompt log leaks.
  • 🛡️ Tamper-Proof Provenance (sign_verify): Cryptographically sign test evidence packs, release binaries, and code diffs with ECDSA or HMAC.
  • 🤝 Inter-Agent Key Exchange (manage_keys): Ephemeral JWK keypairs (RSA-4096, ECDH P-256/P-384) for private agent-to-agent messaging.
  • ⚛️ Post-Quantum Guardrails (pqc_kem_sign): Built-in Kyber KEM and Dilithium signatures future-proof long-term agent artifacts.
  • ⚡ Zero Dependencies: 100% native crypto.subtle execution across Node.js 18+, Bun, browsers, and Edge runtimes.
┌───────────────────────────────────────────────────────────┐
│              Autonomous AI Coding Agent                   │
│     (Antigravity / Cursor / Claude / Copilot / Cline)     │
└─────────┬───────────────────┬───────────────────┬─────────┘
          │                   │                   │
          ▼                   ▼                   ▼
┌───────────────────┐┌───────────────────┐┌───────────────────┐
│ state-memory-mcp  ││ vision-memory-mcp ││     webcrypt      │
│  (Workflow State) ││  (Visual Cache)   ││  (Security Vault) │
│  • Task Graph DAG ││  • UI Grounding   ││  • AES-256 Vault  │
│  • Decisions & SDD││  • Layout Trees   ││  • RSA/ECDH Keys  │
│  • Event Ledger   ││  • Visual History ││  • Digital Sigs   │
└───────────────────┘└───────────────────┘└───────────────────┘

🛠️ MCP Tools Reference (6 Core Tools)

Tool Action / Mode Description
encrypt_payload symmetric | asymmetric | data Encrypt text, JSON objects, or files with AES-256-GCM or RSA-4096.
decrypt_payload symmetric | asymmetric | data Decrypt ciphertext back to plaintext or structured JSON.
manage_keys generate | generate_random_password Generate JWK keypairs (RSA, ECDH, ECDSA, RSA-PSS) or high-entropy passwords.
crypto_hash SHA-256 | SHA-512 | SHA-3 Compute cryptographic hash digests in hex or base64.
sign_verify sign | verify Sign and verify messages, release hashes, and evidence packs.
pqc_kem_sign kyber_* | dilithium_* | hybrid_* Post-quantum Kyber KEM encapsulation and Dilithium signatures.

📚 Technical Documentation Directory

Explore dedicated guides in docs/ and examples/:

Guide Topic
🚀 Live Interactive Playground Test all crypto features in the browser demo.
💻 CLI Reference Guide Scaffolding, global project scanning, and terminal utilities.
⚙️ Multi-IDE MCP Setup Guide Step-by-step MCP JSON configs for all major IDEs.
🔒 Symmetric Encryption API (WebCrypt) AES-256-GCM, streaming files, WebRTC E2EE, PBKDF2.
🔑 Asymmetric Encryption API (WebCryptAsym) RSA-4096 hybrid, ECDH key agreement, ECDSA/RSA-PSS.
⚛️ Post-Quantum Cryptography Guide Kyber KEM, Dilithium signatures, and Hybrid KEM.
🏗️ Architecture & MCP Specifications Stdio JSON-RPC 2.0 protocol and chunk framing specs.
🤖 Agent Skill Definition Custom agent skill with automated test runner script.
📋 Project Instructions Template Multi-agent rules template (<!-- webcrypt-mcp:start -->).
💡 Code Examples Directory Ready-to-run Node.js & browser recipes.

🌐 PuterVision Triad Standard

  • 📊 @putervision/state-memory-mcp: Persistent SQLite graph for workflow states, task DAGs, and decision trails.
  • 👁️ @putervision/vision-memory-mcp: Multimodal visual layout cache, AX grounding, and video replay analysis.
  • 🔐 webcrypt: Zero-dependency cryptographic vault, payload encryption, key management, and digital signatures.

🧪 Testing & Diagnostics

# Run unit & integration test matrix (30 suites, 247 tests)
npm test

# Run live MCP tool test runner (25 assertions, 100% verified)
node .agents/skills/webcrypt-mcp/scripts/exercise_tools.js

# Audit environment & project configuration health
webcrypt doctor

⚖️ License & Disclaimers

Developed and maintained by PuterVision. Released under the MIT License.

  • 100% Local Execution Guarantee: All cryptographic operations execute locally in memory via standard W3C Web Crypto API (crypto.subtle). Zero external API calls, telemetry, or network transmissions.
  • Trademarks & Non-Affiliation: Product names (Cursor, Claude, Google Antigravity, VS Code, GitHub Copilot, Windsurf, Cline, Zed) are property of their respective owners and used solely for compatibility identification.

Facts

Kind
MCP server
Repo
putervision/WebCrypt
Group
Uncategorized
Stars
15
License
MIT
Language
JavaScript
Last push
2026-08-21
Forks
2
MCP Registry
io.github.putervision/webcrypt
Homepage
putervision.github.io/WebCrypt
Topics
cryptography, e2ee, e2ee-encryption, encryption, hmac, jwe, agent-security, agent-security-tools, mcp, mcp-client, mcp-server, mcp-tools, model-context-protocol

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