cipher-gate-0.2.0 is not a library.

Cipher Gate

A proxy RPC that routes signing requests to a browser wallet.

Cipher Gate sits between an EVM dev tool (Foundry, Hardhat, ethers/viem scripts) and an upstream RPC. Read calls pass straight through. Write/sign calls — eth_sendTransaction, personal_sign, eth_signTypedData*, etc. — are intercepted and pushed to a local browser UI, where you approve and sign with a real wallet (MetaMask, Ledger, any WalletConnect/Reown wallet). The signed result flows back to the caller. Your dev tool talks to a plain RPC endpoint and never sees a private key.

 forge / hardhat ──HTTP──▶ cipher-gate ──read──▶ upstream RPC
                              │
                              └─write/sign──▶ browser UI ──▶ your wallet

Install

cargo install cipher-gate

The published crate ships a prebuilt UI, so this needs only a Rust toolchain — no Node.js.

Usage

cipher-gate \
  --rpc-url https://eth.llamarpc.com \
  --reown-project-id <YOUR_REOWN_PROJECT_ID>

Then:

Point your tool's RPC at http://localhost:8545.
Open http://localhost:8545 in a browser and connect a wallet.
Run your tool. Signing requests appear as cards to approve or reject — each shows a transaction simulation result and decoded calldata (with warnings for risky operations like unlimited approvals).

Get a free Reown (WalletConnect) project ID at https://cloud.reown.com. It can also be supplied via the REOWN_PROJECT_ID environment variable.

Options

Flag	Default	Description
`--rpc-url <URL>`	required	Upstream RPC to forward read calls to
`--reown-project-id <ID>`	required	Reown project ID (or `REOWN_PROJECT_ID`)
`--port <PORT>`	`8545`	Port for the JSON-RPC proxy + UI
`--ui-port <PORT>`	—	Serve the UI on a separate port from the proxy
`--host <ADDR>`	`127.0.0.1`	Bind address
`--allowed-origin <ORIGIN>`	—	Extra browser Origin allowed to open the WS (repeatable)

Security

Localhost-only by default. Cipher Gate binds 127.0.0.1, so it is not reachable from other machines. Set --host 0.0.0.0 to expose it on your network — only do this on a trusted network, since anyone who can reach it can drive your wallet. You must then also pass --allowed-origin http://<your-address>:<port>.
Per-run token. Each run generates a secret token embedded in the UI's WebSocket URL; connections without it are rejected.
Origin-checked WebSocket. The signing socket only accepts browser Origins it was told about (loopback by default), blocking other local web pages from connecting.

Development

Requires Rust and Node.js.

# Full build (build.rs builds the frontend if frontend/out is absent)
cargo build --release

# Frontend dev server with hot reload (expects the proxy running on :8545)
cd frontend && npm run dev

# Force-rebuild the embedded UI on the next cargo build
rm -rf frontend/out   # or: CIPHER_GATE_REBUILD_FRONTEND=1 cargo build

See CLAUDE.md for architecture details.

License

MIT