Every mobile wallet
ships OTA. None verify on-chain.

The 2022 Slope hack started with a compromised app bundle — $8M drained, thousands of wallets. OTA is a wider vector. We built the first on-chain verification layer: a Rust SDK that checks every bundle hash against a smart contract before it runs. Open source. Free.

Get the SDK See Coin — the proof

Shipped
proof

Coin First on-chain verified wallet

Built with

Rustkeccak256SolanaEVM / BaseGnosis SafeTauri 2React Native JSIAnchorMulti-sigBundle HashOn-Chain VerifyOpen Source
The problem and the fix

A real attack. A structural fix.
One open source primitive.

OTA supply-chain attacks on wallets are not a future risk — they have already happened. We built the fix as a free open source Rust SDK, then shipped it in a real wallet (Coin) to prove the architecture works. Managed signing and audits are available for teams that want help going live.

The attack takes 3 minutes. The damage is permanent.

Attacker breaches CI/CD. Injects one line into the JS bundle. Pushes to CDN. Every user downloads it silently on next open. Seed phrases exfiltrated. This isn't theoretical — the 2022 Slope wallet hack started exactly this way. $8M drained. One update. Zero warning.

  • Slope Hack
  • Supply Chain
  • Real Incident

The fix: hardware wallet as final gatekeeper.

Before any update runs, the Rust verifier hashes the bundle and queries the on-chain registry. If the developer's hardware wallet didn't sign that exact hash — the update is rejected silently. The attacker owns your CI/CD, your CDN, your signing server. They don't own your Ledger.

  • Rust Native
  • On-chain registry
  • Hardware wallet

Free SDK. MIT licensed.

Open source Rust crate on crates.io. Integrate in a weekend. React Native JSI wrapper included. Free forever.

  • Open Source
  • crates.io

Managed signing for teams.

Don't want to run your own multi-sig quorum? We operate it. Sub-5-minute publish. 99.9% SLA.

  • $2k/mo
  • 99.9% SLA

Crypto wallets only.

Not a general security firm. Every line of code we write protects users who hold real funds.

  • Specialist
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Shipped proof

We built it ourselves first. Then open sourced it.

Coin is a fully functional non-custodial wallet with on-chain OTA verification running in production. We built it to prove the architecture ships — not just in theory. The full source is open. Audit every line before you integrate ours.

Coin Dev

We built the first non-custodial wallet with on-chain verified OTA updates — and open sourced it. Every bundle hash is checked on-chain before it runs. Audit every line.

Reference implementation

Who we build for

Mobile wallet teams React Native or Tauri wallets shipping OTA updates to users who hold real funds — and have no on-chain verification today.
DeFi apps with embedded wallets Apps that manage user keys inline. A supply-chain compromise doesn't just break your app — it drains every connected wallet.
Wallet-as-a-service platforms Your downstream clients trust you with their users' keys. One compromised update across your fleet is a catastrophic incident.
Post-incident recovery teams If you've been hit or narrowly avoided it, on-chain OTA verification is the one control that closes the gap permanently.
One high-profile OTA attack ends a wallet product.

You don't get a second chance
when users' funds are gone.

Start with the free SDK. If you want velm to manage the signing infrastructure, we're available for a 30-minute call to scope it. No funnels. Directly to Divyam.

Get the SDK See pricing

SDK is free and open source. Managed signing starts at $2,000/mo.

Velm