SatSigner is self-custody Bitcoin software. Vulnerabilities here can put user funds at risk, so we ask reporters to follow the process below and give us a chance to ship a fix before details become public.

Do not open a public GitHub issue for security vulnerabilities.

The only way to contact the project privately is Nostr:

• Send a NIP-17 gift-wrapped direct message (kind 1059) to npub1ewv0j6l7fplmadqmcmdywkff2snham403sensqlqavymt7fx7jfs58e60d, published only to that account's inbox relays — the DM relay list advertised in its kind 10050 event. Any NIP-17-capable client resolves the inbox relays and delivers the gift wrap automatically.
• Do not use legacy NIP-04 DMs — they expose metadata and are not monitored. Do not broadcast the gift wrap to public relays beyond the inbox set.
• Reports sent through any other channel (GitHub issues, discussions, pull requests, public notes) are treated as public disclosure.
• You may report from a throwaway npub to remain pseudonymous.

Please include:

• A description of the vulnerability and its potential impact
• Affected version(s) and platform(s) (iOS / Android)
• Steps to reproduce or a proof of concept
• Any suggested remediation, if you have one

• Acknowledgement within 72 hours
• Initial assessment (severity, affected versions, remediation plan) within 7 days
• Status updates at least every 14 days until resolution
• Coordinated disclosure — we aim to release a fix before any public disclosure and will agree on a disclosure timeline with you. We credit reporters in the release notes and the published advisory unless you ask to remain anonymous.

We do not currently run a paid bug bounty program.

In scope — issues in SatSigner code that could lead to:

• Theft or loss of funds (key/seed extraction, transaction manipulation, malicious address substitution, PSBT tampering)
• Exposure of secrets at rest (mnemonics, keys, PIN/Passphrase material, Nostr keys, RPC credentials)
• Bypass of authentication or duress-PIN behavior
• Cryptographic weaknesses in our usage (key derivation, encryption, random number generation)
• Network attacks against the app (cleartext traffic, malicious Electrum/Esplora/Nostr relay behavior not already covered by the trust assumptions below)

Out of scope:

• Vulnerabilities in third-party dependencies that are not exploitable through SatSigner (report them upstream instead)
• Attacks requiring a rooted/jailbroken device, physical access to an unlocked device, or a compromised operating system
• Social engineering, phishing, or compromised user devices/accounts
• Denial of service of public infrastructure (relays, Electrum servers)
• Issues in the docs site or CI that do not affect the shipped app

Only the latest released version of SatSigner receives security fixes. Fixes ship in a new release; we do not backport patches to older versions.

SatSigner is designed to minimize trust in networked services, but some trust assumptions remain:

• Electrum/Esplora servers see the addresses you query. Use your own node or connect over Tor for privacy.
• Nostr relays are used for label sync and account backup; sensitive payloads are encrypted client-side before leaving the device.
• Device security is foundational: seed words and keys are encrypted at rest and gated by the device keystore and your PIN, but no app can protect secrets on a compromised operating system.

Release builds are published on GitHub Releases and on Zapstore, where releases are attested by the project's Nostr identity (npub1ewv0j6l7fplmadqmcmdywkff2snham403sensqlqavymt7fx7jfs58e60d). Only install builds obtained from these official channels.