1Password Ephemeral EVM Signer

In progress

EthereumSecurity1PasswordSepoliaCLI

Shows every transaction field before a test key signs an Ethereum payload, then stops without broadcasting. Demonstrates policy-shaped signing controls relevant to how digital assets actually move.

Technical Python, 1Password CLI, and eth-account build a Sepolia EIP-1559 payload through an stdin-only secret pipe; validation precedes key access and the tool records the remaining transient RAM exposure.

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Source

GitHub →

Demos

Short and full walkthroughs play inline on the project page.

Short demo →Full demo →

Case Study

Problem

I want a demoable signing path that keeps private keys out of the repo, .env files, and CLI argv, while still making the review surface explicit before any key material is read.

What I designed and implemented

1Password reference + op read stdin pipe into a local Python signer
Pre-key review of Sepolia type-2 fields: destination, value, nonce, gas, fee caps, calldata, access list
Reject unsupported fields before any key access
Static project page on Vercel with walkthrough media

Architecture

op read resolves a vault reference to stdout
sign-with-1password pipes that stream into op-evm-sign
Signer validates the reviewed EIP-1559 schema, then signs in process RAM
Output is from address, rawTransaction, and transactionHash only; no RPC broadcast

Engineering decisions

Demonstrate no plaintext private-key file on the host, not non-exportable custody
Keep the key reference Git-ignored so vault/item identifiers stay private
Pair with airgap-tx-signer for the hardware path where key material never reaches host memory

Verification and testing

Regression suite via make test
Deterministic screenshot kit for review, rejection, and release states
Published short and detailed YouTube walkthroughs

Limitations and what is simulated

Compromised host, memory inspection, swap, and crash dumps are out of scope
Not a hardware wallet or KMS-backed custody solution
Demo Sepolia key only; never fund meaningful value

Production differences

Production custody would use hardware confirmation or cloud HSM keys that never enter application RAM

Video demos