dev-crypto-toolkit

Developer cryptography utilities — REST API + MCP server.

All operations use Node.js built-in crypto module. No external APIs, no secrets leave your machine.

Features

• JWT — Decode tokens (inspect header/payload without verification)
• Hash — MD5, SHA1, SHA256, SHA512, HMAC
• Base64 — Encode / Decode
• URL — Encode / Decode
• UUID — v4 generation (bulk)
• Password — Generation with configurable length & complexity
• Random — Cryptographically secure hex/bytes/base64
• Password Hashing — PBKDF2-SHA512 hash & verify
• Timestamp — Unix ↔ ISO ↔ human readable conversion
• String Encoding — ROT13, Caesar cipher

Quick Start

npm install
npm start        # REST API on http://localhost:4300
npm run mcp      # MCP server (stdio)

Docker

docker build -t dev-crypto-toolkit .
docker run -p 4300:4300 dev-crypto-toolkit

API Endpoints

| Method | Endpoint | Description | |--------|----------|-------------| | POST | /api/v1/jwt/decode | Decode JWT token | | POST | /api/v1/hash | Hash string (md5/sha1/sha256/sha512/hmac) | | POST | /api/v1/base64/encode | Base64 encode | | POST | /api/v1/base64/decode | Base64 decode | | POST | /api/v1/url/encode | URL encode | | POST | /api/v1/url/decode | URL decode | | GET | /api/v1/uuid?count=5 | Generate UUIDs | | GET | /api/v1/password?length=16&count=5 | Generate passwords | | POST | /api/v1/password/hash | Hash password (PBKDF2) | | POST | /api/v1/password/verify | Verify password hash | | GET | /api/v1/random?bytes=32&format=hex | Random bytes | | POST | /api/v1/timestamp | Convert timestamps | | POST | /api/v1/encode/rot13 | ROT13 | | POST | /api/v1/encode/caesar | Caesar cipher |

MCP Configuration

Add to your MCP client config:

{
  "mcpServers": {
    "dev-crypto-toolkit": {
      "command": "node",
      "args": ["/path/to/dev-crypto-toolkit/src/mcp-server.js"]
    }
  }
}

Examples

# Decode JWT
curl -s -X POST http://localhost:4300/api/v1/jwt/decode \
  -H 'Content-Type: application/json' \
  -d '{"token":"eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0.dozjgNryP4J3jVmNHl0w5N_XgL0n3I9PlFUP0THsR8U"}'

# SHA256 hash
curl -s -X POST http://localhost:4300/api/v1/hash \
  -H 'Content-Type: application/json' \
  -d '{"text":"hello world","algorithm":"sha256"}'

# Generate 5 UUIDs
curl -s 'http://localhost:4300/api/v1/uuid?count=5'

# Generate passwords
curl -s 'http://localhost:4300/api/v1/password?length=24&count=3'

# Timestamp conversion
curl -s -X POST http://localhost:4300/api/v1/timestamp \
  -H 'Content-Type: application/json' \
  -d '{"timestamp":1700000000}'

License

MIT