An honest comparison
There are six reasonable ways to hold your own bitcoin, and SignerOS is better than the others at three things and worse at four. This page says which, in a table you can argue with.
The author of one of the six. That is a real bias and no disclaimer removes it, so here is the practical version: every claim in the SignerOS column is checkable against the source code, and the rows where it comes last are marked in red rather than left out. If you find a row that flatters it unfairly, that is a bug worth reporting.
Nothing here is a ranking. A setup that is wrong for €200 is right for €200,000, and the reverse.
All six are self-custody: you hold the key, nobody can freeze your coins, and nobody will help you if you lose your backup. They differ in what has to be trusted while a transaction is being signed.
Air-gapped · full node workflow
A machine that never goes online runs Bitcoin Core and signs PSBT files; a second machine with your own node builds and broadcasts them.
Best at: trusting nobody. Your own node validates the rules, your own software builds the transaction, no third-party server sees your addresses.
The cost: two machines, a synced node, hundreds of gigabytes, and a general-purpose OS whose networking is disabled only by your discipline.
Amnesic live OS · offline signing
Boot Tails from a stick, run Electrum in offline mode, sign a transaction exported from an online Electrum, and carry it back.
Best at: maturity per euro. Tails and Electrum are both years old, widely used and reviewed by people with no stake in them.
The cost: Tails is built to reach the internet through Tor. The network stack is there, so the air gap is a rule you keep, not a property of the system.
Air-gapped by construction · RAM only
A USB image that turns a computer you already own into a signer with one job. No network code is compiled into the kernel at all, and nothing survives power-off.
Best at: removing choices. There is nothing to configure, no browser, no drives visible, nothing to leave behind, and nothing to buy or ship.
The cost: new and unaudited, no secure element, no PIN, and you type your recovery words at the start of every session.
Online · keys on the machine
Sparrow, Electrum or similar running on your everyday computer, with the key stored on its disk.
Best at: capability. The full desktop toolset — coin control, labelling, multisig coordination, your own node — with nothing to plug in.
The cost: the key lives on an online, general-purpose machine. Any malware that reaches your user account can wait for you to unlock the wallet.
Online · hardware-backed storage
A mobile wallet holding its own key, protected by the phone's screen lock and its hardware keystore.
Best at: actually being used. Fast, in your pocket, hard to lose, and the platform is patched more reliably than most desktops.
The cost: always online, dozens of other apps, and a screen you cannot fully trust once the device is compromised.
Purpose-built · key never leaves
A small device that keeps the key inside it for life and returns signatures over USB, SD or QR.
Best at: physical security. A secure element on most models, a PIN, wipe-after-N-attempts, tamper-evident packaging and a display that does one thing.
The cost: you buy it, so somebody makes it and somebody ships it. Firmware openness varies, secure-element code is usually closed, and the vendor is a party you trust.
Green is a genuine strength, amber is "fine, with a condition attached", red is a real weakness. The SignerOS column is tinted so you can see it being marked down.
| Offline PC + Core | Tails + Electrum | SignerOS | Hot wallet (PC) | Hot wallet (mobile) | Hardware wallet | |
|---|---|---|---|---|---|---|
| Is the signing machine online? | NO, BY RULEThe network stack is present and disabled by you | NO, BY RULETails is built for Tor; offline is a mode you choose | NO, BY BUILDNo network code in the kernel; the build fails if that changes | YES, ALWAYSSigning happens on a connected machine | YES, ALWAYSSigning happens on a connected machine | NOUSB, SD or QR only; the paired app is the online half |
| What must be trusted while signing | A WHOLE OSDesktop Linux plus Core, both large but heavily reviewed | A WHOLE OSTails plus Electrum, both large and heavily reviewed | ONE APPA stripped kernel and a single kiosk binary; no shell, no browser | EVERYTHINGEvery program on your daily machine | OS + SANDBOXThe app is isolated, but the platform is not yours | SMALL FIRMWAREPurpose-built, minimal, often with a secure element |
| Can the key exist on an online machine? | NEVER | NEVER | NEVERThe signer cannot reach a network even if it wanted to | IT LIVES THERE | IT LIVES THERE | NEVERIt does not leave the device at all |
| What remains after you finish | AN ENCRYPTED WALLETOn the offline machine's disk, as strong as its passphrase | NOTHINGUnless you enable persistent storage | NOTHING, EVERRAM only; free memory is scrubbed at shutdown | THE KEYOn the disk of a machine that is online | THE KEYIn hardware-backed storage on the device | THE KEYInside the device, which is the design |
| If the device is stolen | DISK ENCRYPTIONWhatever you set up is what protects it | LITTLE TO TAKEA stick with no key on it, unless persistence is on | NOTHING TO TAKEThe stick holds no key — but your paper backup is everything | SCREEN LOCK ONLYThen the wallet's own passphrase, if you set one | PIN + KEYSTOREGenuinely hard to extract from a modern phone | PIN + WIPEDesigned to survive being in the wrong hands |
| Tamper resistance of the hardware | NONEAn ordinary PC | NONEAn ordinary PC | NONEAn ordinary PC, and its firmware is below anything this can control | NONE | SOMESecure enclave, verified boot | THE POINT OF ITSecure element, epoxy, tamper-evident packaging |
| Supply chain: what you must trust | NOTHING NEWHardware you already own | NOTHING NEWHardware you already own | NOTHING NEWYou buy nothing, so nothing can be swapped in transit | NOTHING NEW | PHONE VENDOR | A SHIPPED DEVICEVendor, distributor and courier are all in the path |
| What you see before approving | FULL DETAILA large screen and complete transaction data | FULL DETAILA large screen and complete transaction data | FULL DETAILAmount, destination and change re-derived from the file itself; refuses an unknown fee | FULL DETAILOn a screen malware could be drawing | FULL DETAILOn a screen malware could be drawing | A SMALL SCREENDedicated and trustworthy, but cramped for complex scripts |
| Independent review and age | HIGHESTBitcoin Core is the most examined code in Bitcoin | HIGHYears of use, external audits, a large community | LOWEST HERENew, one author, no external audit. Reproducible, but not yet reproduced by a second machine | HIGHFor the established wallets | VARIESWide gap between the best and the worst apps | GOOD, UNEVENMature vendors; secure-element firmware is usually closed |
| Privacy of the online half | YOUR OWN NODENobody learns your addresses | PUBLIC SERVERSOver Tor by default, or point it at your own | NOT ITS JOBThe signer talks to nothing; privacy depends on the watch-only wallet you pair it with | DEPENDSOwn node or a vendor's server | USUALLY A SERVERMost mobile wallets query a backend | THE APP'S BACKENDUnless you pair it with your own node |
| Cost and effort to set up | HIGHESTTwo machines, a full node, real patience | LOWA stick and an evening | LOW, THEN FIDDLYFree and a stick, but the first build takes 30–90 minutes if you compile it yourself | LOWESTInstall and go | LOWESTInstall and go | €50–200Then a short setup |
| Friction per transaction | HIGHExport, carry, sign, carry back, broadcast | MEDIUMBoot the stick, sign, carry it back | HIGHBoot a machine and type your recovery words every single time | NONEClick send | NONETap send | LOWPlug in, check the screen, press a button |
// "By rule" versus "by build" is the distinction the whole table turns on. An offline PC and a Tails stick are both genuinely air-gapped while you are careful; SignerOS is air-gapped while you are careless, because the kernel has no networking compiled into it and the build refuses to produce an image if that ever stops being true. That is one property, not a general claim of superiority — the same table has it last on two rows.
If you only read one section of this page, read this one. A comparison written by an author is only worth anything where it goes against the author.
It is new, it was written by one person, and no external security review has been done. Bitcoin Core, Electrum and the established hardware vendors have years of adversarial attention that this project simply has not had. Reproducible builds are not a substitute for review — they prove the binary matches the source, not that the source is right.
A hardware wallet is built to be captured: PIN, wipe-after-N-attempts, a chip designed to resist someone with the device on a bench. SignerOS has none of that, because it is software on a computer. Its answer is that the stick holds no key at all — which is a different design, not a stronger one. Everything rests on your paper backup and, if you use one, your passphrase.
It boots on an ordinary PC, and the UEFI firmware, the management engine and anything implanted in the machine all sit below the operating system. Secure Boot support is in the build but has never been tested on real firmware, and the released images are unsigned on purpose. An old laptop with no valuables in it is the sensible way to run this.
Nothing persists, which is the feature and also the friction: every session begins by entering twelve or twenty-four words on a keyboard. That is slow, it is easy to mistype, and it is a moment where a camera or a person behind you matters. A hardware wallet asks for a PIN.
Most self-custodied bitcoin that gets lost is not stolen by an attacker. It is lost because the only backup was destroyed, thrown away, or never written down properly in the first place. Choosing between these six matters far less than writing your recovery words on something durable and keeping it where a fire or a burglary cannot take both it and you. Any of the six with a good backup beats the best of them without one.
Not in every way, and saying otherwise would be dishonest. It is stronger on supply chain (you buy nothing, so nothing can be tampered with in transit), on network isolation (no network code at all, rather than a stack left unplugged) and on leaving no trace (RAM only, forgotten at power-off).
A hardware wallet is stronger on physical security — a secure element, a PIN, wipe-after-N-attempts, a display that does one job — and on maturity, because established vendors have years of external review that a new project does not.
Independent review, physical protection, everyday convenience, and — for now — the reproducibility claim itself: the build has been measured on one machine, and nobody else's number has come back to confirm it. Those four are the section above, and they are the honest reasons to choose something else.
For many people, yes. Tails is amnesic, widely used, and reviewed far more than this project is; Electrum's offline signing workflow is well established. The difference is that Tails has a full network stack and is designed to reach the internet through Tor, so an offline session is a discipline you maintain. SignerOS has no networking compiled in, which takes the discipline out of it — and takes every other use of that machine with it.
Yes, and it is one of the better uses of it. A multisig wallet whose signers are different kinds of device is not exposed to a single vendor, a single firmware bug or a single supply chain. SignerOS exports BIP48 cosigner keys for this, and verifies P2WSH and P2SH-P2WSH change against the witness script when it signs.
Not for the amount you would carry in a pocket. Modern phones keep app secrets in hardware-backed storage and are patched more reliably than most desktops, so a good mobile wallet is a reasonable place for spending money. It is an online, general-purpose device running dozens of other programs, which is why it is a poor place for savings.
Anything below the operating system on the machine you boot: compromised UEFI firmware, a management engine, hardware implanted in the computer itself. It does not protect a recovery phrase you have typed into a phone, photographed, or put in a cloud drive. It does not protect you from losing your only backup, which is how most self-custodied bitcoin is actually lost. And it cannot help if somebody is standing in front of you demanding that you sign.