Thirty products against ten deliverables. Open any row for what it is, what it costs you, and every incident on the public record.
| The product | No signing role | You make the key | Your own dice | Keeps nothing | Truly air-gapped | No chip to trust | No attestation | No vendor needed | Unlimited keys | Start over anytime | Score |
|---|---|---|---|---|---|---|---|---|---|---|---|
KŌINIkeystickbootable appliance | 10/10 | ||||||||||
| Hardware signers | |||||||||||
LedgerNano S Plus · X · Flex · Stax | 1/10 | ||||||||||
TrezorOne · Model T · Safe 3/5/7 | 2/10 | ||||||||||
ColdcardMk3 · Mk4 · Mk5 · Q | 3/10 | ||||||||||
BitBox02Multi · Bitcoin-only · Nova | 2/10 | ||||||||||
BitkeyBlock · 2-of-3 multisig | 0/10 | ||||||||||
Blockstream JadeJade · Jade Plus | 2/10 | ||||||||||
Foundation PassportCore · Prime | 4/10 | ||||||||||
KeystoneEssential · 3 Pro | 4/10 | ||||||||||
NGrave ZERO | 4/10 | ||||||||||
Ellipal TitanTitan · Titan 2.0 | 2/10 | ||||||||||
TangemNFC card | 1/10 | ||||||||||
SafePalS1 · S1 Pro · X1 | 2/10 | ||||||||||
ArculusNFC card | 1/10 | ||||||||||
Cypherock X1vault + 4 cards | 2/10 | ||||||||||
GridPlus Lattice1 | 1/10 | ||||||||||
D’CENTBiometric | 1/10 | ||||||||||
KeepKey | 4/10 | ||||||||||
OneKeyClassic 1S · Pro | 3/10 | ||||||||||
| DIY signers | |||||||||||
SeedSignerself-built | 9/10 | ||||||||||
Kruxself-flashed | 8/10 | ||||||||||
Specter DIYself-built | 6/10 | ||||||||||
Jade DIYflashed onto generic board | 5/10 | ||||||||||
| Software cold storage | |||||||||||
Bitcoin Core air-gaptwo machines | 6/10 | ||||||||||
Electrum offlineoffline wallet file | 6/10 | ||||||||||
Tailsamnesic live OS | 6/10 | ||||||||||
Border Walletsmemorised grid | 9/10 | ||||||||||
| Bearer instruments | |||||||||||
Opendimeone-shot bearer stick | 2/10 | ||||||||||
BalletREAL Series metal card | 5/10 | ||||||||||
Material Bitcoinengraved steel plate | 5/10 | ||||||||||
KŌINIkeystickbootable appliance | 10/10 | ||||||||||
Scroll the table sideways
Every product in the three largest groups answers the first question the same way: once your key exists, the product still needs it. A hardware wallet keeps it inside a chip and signs with it for as long as you hold the coins. A DIY signer forgets it at power-off and then asks for it again, every time you spend. Software cold storage writes it to a disk.
The only products that escape the signing role are bearer instruments — and all three of those escape it by having the manufacturer generate your key before the product ships. They trade a device in the path for a factory in the past, which is the worse half of the trade, because you cannot audit a factory after the fact and you cannot ask it to do it again.
We are not a vault. We are the delivery room.
One row carries every mark. It is not because the other products are badly made — several are excellent, and the people who build them are serious. It is because they are all answering a different question: how do I guard a key that already exists? We only ever answered one: how should a key be born, so that nothing has to guard it afterwards?
SeedSigner is the strongest product here that isn’t ours, and it earns nine marks. The one it misses is the first — the key goes back onto a device every time you spend. That column sits on the left because it decides the rest.
What it is, what it costs you, and every documented incident with its source. Closed by default — read only the ones you care about.
A RAM-only bootable environment, or a sealed-window Mac app. It draws entropy, mixes in dice you rolled yourself, derives a BIP-39 seed and its receive addresses, shows them once, and is destroyed at power-off. It does not sign. It does not store. It never needed a network.
Nothing persists and nothing signs, so after the ceremony there is no device, no company and no chip standing between you and your key. The key exists where you wrote it down and nowhere else.
Closed source, with an independent review of the entropy path. The dice you roll are strong enough to carry the seed on their own, so you are never required to trust our randomness to reach the security target.
USB and, on most models, Bluetooth and NFC. Keys are generated by the chip's own TRNG, stored in a certified secure element, and signed with on request. Ledger Live performs a genuine-device check on connection.
No user entropy anywhere in the path. Secure-element firmware is under NDA; an independent reviewer's verdict is that the product cannot be independently audited. The key is generated by a chip you cannot inspect and lives there for the life of the device.
In May 2023 an official Ledger account stated publicly that it is and always has been possible to write firmware that facilitates key extraction. The post was deleted the next day and called confusing wording. The CTO's follow-up conceded that a provider wanting a backdoor could place it in the random number generator, the crypto library, or the hardware.
UnchainedA 2020 breach exposed names, postal addresses and phone numbers of roughly 292,000 customers, followed by phishing waves and documented fears of home invasion.
DecryptA second, separate customer-data leak through an e-commerce partner was confirmed in January 2026.
SiliconANGLEA December 2023 supply-chain attack on Ledger's Connect Kit drained roughly $600,000 from users of web applications. The hardware itself was not affected.
The Hacker NewsUSB, with Bluetooth on the Safe 7. Firmware is open source. Entropy mixes randomness from the host computer with the device's own generators, and newer firmware adds an Entropy Check. The Safe 7 ships TROPIC01, a secure element auditable down to the silicon.
The Entropy Check is weaker than it sounds, and Trezor says so: it cannot check the wallet you keep. Only discarded candidates are checked, so it deters a device that cheats every time rather than proving anything about your seed. And host entropy is the computer's randomness, not yours.
Kraken Security Labs published an attack in 2020 requiring about fifteen minutes of physical access: voltage glitching dumped the flash, and a four-digit PIN fell in under two minutes on a single CPU core. Kraken stated the flaw lies in the microcontroller and that fixing it would require a hardware redesign.
Kraken Security LabsResearchers demonstrated an SRAM dump during firmware update at 35C3 in 2018, alongside a PIN side-channel found by Ledger's research lab.
TrezorA support-portal breach disclosed in January 2024 exposed contact details for roughly 66,000 users.
HackreadmicroSD and USB-C, with NFC and QR on newer models. Open-source firmware, dual secure elements from deliberately different vendors, and — importantly — support for D6 dice entropy that can complement or fully replace the device generator.
The dice path is the only reason anyone survived what happened here. It is also optional, buried behind a setup choice most buyers never make. The key is still generated into a secure element, and the device still signs for the life of the wallet.
In July 2026 attackers swept roughly 594 BTC in twenty-five minutes. Total losses across several waves are estimated between $116M and $145M. The cause was a firmware build guard that tested whether a macro was defined rather than whether it was enabled — so a value of zero passed the check, and the runtime silently used a software generator seeded from a chip ID and a timer instead of the hardware source. Effective entropy fell to about 2^40 on some models. The code shipped in March 2021 and was found by attackers, not auditors, five years later.
Block Engineering · TRM LabsThe device's own randomness health check passed throughout, because a deterministic generator still produces differing adjacent values. Statistical sanity checks do not catch this class of failure.
Block EngineeringUsers who supplied their own dice entropy were unaffected. Users who relied on a passphrase were not protected — the vendor's initial guidance on that point did not hold, and passphrase holders lost funds.
CasaThe strongest published entropy design among signing devices: five sources combined, including randomness from the host computer and a hash of your device password, so the result is as strong as the strongest surviving source. Fully open source with reproducible builds, published schematics and X-rays.
It is still a device that generates your key, keeps it, and signs with it. And its own recent history settles the question of whether open source is enough: it shipped a severe bootloader flaw for years, in public, where anyone could have read it.
In August 2026 BitBox fixed three vulnerabilities, including a severe bootloader flaw that could allow malicious firmware to be loaded onto a genuine device following a successful phishing attack. The company found them itself, using AI models during internal review, and disclosed them publicly. No funds were lost.
DecryptA hexagonal device with a fingerprint sensor, paired to a phone over NFC, from Block — Jack Dorsey’s company. Launched December 2023, shipping since March 2024. There is no seed phrase. The wallet is 2-of-3 multisig: one key in the device’s secure enclave, one in the mobile app backed up to your cloud account, and a third held by Block on its own servers. Any two of the three move funds.
A key to your money is generated and held by the vendor, as a constituent part of your wallet. Block states it cannot spend alone, and that is accurate — but the key exists, on their infrastructure, for as long as the wallet does. There is no seed phrase to write down, so there is no form in which you can take your keys and walk away.
Block is explicit about this architecture rather than hiding it, and the design genuinely protects against losing your phone or your device. The trade is stated plainly: you are buying recovery, and the price is a vendor key inside your wallet.
No breach, CVE or published exploit found.
Fully open source, with no secure element by deliberate choice. Instead a virtual secure element splits your encrypted key with a blind oracle server that never learns your PIN. Entropy is the best-documented of any device here. A stateless mode exists where the phrase is entered per session.
Unlocking requires the oracle to be reachable over the network in normal use. The server is open source and self-hostable and cannot spend your coins — but it is a liveness dependency on infrastructure in the path to your own money.
Ledger's research lab recovered the firmware decryption key from the ESP32 chip by power analysis, published 2023, enabling evil-maid address substitution with physical possession.
Ledger DonjonA December 2025 disclosure described a missing size check that could, at worst, lead to secret key extraction on an unlocked device. Fixed in 1.0.37.
BlockstreamThe Core is the cleanest air gap in the industry: QR and microSD only, with USB-C wired for power with no data pins. Open firmware and published schematics. The Prime is a different proposition — NFC and an encrypted Bluetooth link.
The air gap is real. It is also beside the point: the key is generated on the device, stored on the device, and signed with by the device for as long as the wallet exists. An air gap protects the channel, not the custody.
A 2025 third-party audit of the Prime returned five low-severity findings, none directly exploitable, including that code to clear secure memory after a final failed PIN attempt had been removed during development. Foundation restored it and fixed all five.
KeylabsQR-code signing with a microSD alternative, three secure elements, fingerprint unlock with a PIN fallback, and a dice-roll option for the recovery phrase. Application firmware is public; the microcontroller library and secure-element firmware are not.
Keystone offers dice specifically because secure-element internals cannot be shown — their own framing. The entropy construction XORs several sources, which is the same shape that failed silently elsewhere.
A 2023 audit found that one of the XORed entropy inputs came from an unauthenticated command a physically-present attacker could use to inject low-entropy data. Fixed and retested. The same audit found tamper events were logged without write confirmation, which could be evaded.
KeylabsQR-only for transactions, with USB-C for charging and updates. The company markets a key generated from the secure element, a light sensor and user-supplied randomness including a fingerprint, plus a shuffle step.
The construction is not published. How these inputs combine, or how their quality is measured, is not documented anywhere, and the secure element and operating system are closed. A fingerprint is a low-entropy identifier you leave on every surface you touch, not a secret.
NGrave markets an EAL7 rating. The claimed scope differs between NGrave's own materials and third-party coverage, and no certificate identifier or certifying body is published. No breach or vulnerability has been documented — the issue is that the claims cannot be checked.
No breach, CVE or published exploit found.
QR-only transactions with firmware updates by microSD. Mostly closed source. The current model claims an EAL5+ secure element without naming the manufacturer or part.
The companion app is effectively required to build and broadcast transactions. The original generation was built on a low-cost smartphone system-on-chip.
The findings below date from 2019 and a revised device followed. The architecture, the closed source and the unnamed chip did not change.
Ledger's research lab found a WiFi chipset physically present and functional in factory mode on a device marketed as air-gapped. The air gap was implemented in software only.
Ledger DonjonThe same teardown dumped flash through reconnectable USB data lines and recovered users' encrypted extended private keys. The password check was a fast salted hash — an eight-character random password was estimated crackable in minutes on a desktop. There was no genuineness check, making pre-seeding viable.
Ledger DonjonEllipal acknowledged that a marketing image had made inaccurate security claims and removed it.
EllipalAn NFC card tapped against a phone. The key is generated on-chip at activation inside a certified secure element and signs there. Firmware is closed, burned once, and never updatable — the company describes this as security through obscurity.
No user entropy. Nothing to inspect. On seedless cards the key cannot be extracted at all; where a phrase is offered it is shown once and can never be viewed or exported again, and you cannot add one to an existing wallet.
In December 2024 an application logging bug wrote private keys into app logs, which were then attached to support tickets and became visible in email histories and the ticketing system. Tangem confirmed the bug and said affected logs were deleted. Criticism focused on the quiet handling; the original public report was removed.
Yahoo TechThe S1 signs by QR with no USB data path, no Bluetooth and no NFC. The X1 uses Bluetooth and is not air-gapped despite the shared branding. Open-source claims differ between the company's own pages.
Entropy rests on an unauditable secure element. The company's openness claims are inconsistent across its own materials.
Kraken Security Labs found tamper detection ineffective, potting compound that could be heated and scraped away to permit a full flash dump, and a firmware downgrade attack that went undetected. Kraken also reported the firmware bundles GPL-licensed components and that SafePal declined to provide source on request. The downgrade issue was fixed.
Kraken Security LabsA breach disclosed in August 2026 exposed names, physical addresses and contact details for 39,798 customers, and the data was offered for sale. No keys or funds were affected.
CoinDesk · BleepingComputerAn NFC card tapped against a phone alongside a PIN and the phone's own biometric unlock. The secure element generates and holds the keys. A twelve-word phrase is shown once at setup.
Closed firmware, a certification claim with an undisclosed chip, and a closed companion app that is the only interface. No vulnerability has been documented.
No breach, CVE or published exploit found.
USB by explicit design choice — the company argues QR air gaps add little because firmware updates need a cable anyway. The key is split by secret sharing across four NFC cards and the vault, marketed as having no seed phrase.
Sharded persistence is still persistence, and the device still reconstitutes and signs. The vault accepts only cards carrying the company's own certificate, which is vendor lock-in at the hardware level. The card firmware is proprietary and cannot be upgraded.
No breach, CVE or published exploit found.
An internet-connected device, by architecture, over WiFi or Ethernet. A general compute environment receives signing requests online and passes hashes to an isolated secure environment that holds the keys.
Closed source. An independent reviewer's published verdict is that the product cannot be independently audited. It accepts only cards bearing a GridPlus certificate. No breach has been documented — the problem is that nothing can be checked.
No breach, CVE or published exploit found.
Bluetooth and USB, with a fingerprint sensor that approves transactions. The key is generated and held in a certified secure element.
The company states plainly that its generation uses no extra entropy mixing and does not rely on user input. That is the clearest confirmation in the industry that the user contributes nothing to their own randomness.
The September 2025 incident below affected the mobile application, not the hardware wallet — unless a hardware device's phrase had also been restored into the app.
Unauthorized transfers across several chains began in September 2025. Researchers quoted in Korean press attributed the cause to weak randomness in how older application versions generated keys; the company has not confirmed the mechanism. One tracker counted roughly two million XRP taken from 1,552 wallets in about two hours.
BlockheadThe company's own remedy was that updating was not enough: users had to create a new wallet with a new recovery phrase, because reusing the existing phrase may regenerate the same or a related key.
BlockheadUSB only. Open source with published reproducible build instructions. Its own documentation states the production design uses a general-purpose microcontroller rather than a dedicated secure element.
No secure element, no documented entropy source, and two published vulnerabilities on top of inheriting the glitching attack from the design it derives from.
A 2019 vulnerability allowed crafted messages to partially reset cryptographic secrets to known values, requiring no authentication and reachable over WebUSB. Rated high severity.
TenableA 2023 buffer overflow could reveal device memory on screen; with physical access to an unlocked device an attacker could extract the recovery phrase.
GCVEThe Pro supports QR air-gapped signing alongside USB, Bluetooth and NFC, with fingerprint unlock. Firmware is claimed open and reproducible.
No user entropy documented. The hardware randomness source is not named.
In February 2023 a security firm extracted the recovery phrase by using an FPGA to intercept unencrypted communications between the processor and the secure element. OneKey acknowledged it publicly, paid a bounty and shipped a patch, noting the attack needs physical possession and specialist equipment.
The BlockA self-built device from about fifty dollars of parts. Stateless — it holds a seed in memory only while powered. Entropy is entirely user-supplied, from dice, coin flips or a camera photograph. There is no device generator in the seed path at all. Signing happens by animated QR code.
It is a signer. The seed must be re-entered — typed, or scanned from a hand-drawn QR of your own mnemonic — every single time you spend. That is a device back in the path on every transaction, by design.
You assemble it yourself from parts of unknown provenance and check the firmware yourself. Most people will not. And none of that changes the central fact: every spend puts your seed back onto a device.
The SeedQR convenience feature is a plaintext seed in optical form. Anyone who photographs it has the wallet.
BlockstreamOpen-source firmware flashed onto inexpensive boards. Entropy from dice, coin flips or camera, hashed and displayed so you can check it independently. Optionally persists encrypted mnemonics to flash or SD card.
A signer, with optional statefulness. Its own documentation marks camera entropy experimental and warns that its quality metrics are approximations rather than cryptographic values, and recommends dice instead.
Its own README states the software has not been formally audited by a third party. Boards are bought from arbitrary suppliers — which is why the project ships an experimental tamper-check tool.
No breach, CVE or published exploit found.
A self-built signer from off-the-shelf development hardware. Two modes: one forgets secrets at power-off, and one persists them to microcontroller flash.
The project named the persistent mode reckless mode. Its entropy architecture is not published anywhere. The repository points to a roadmap of what must still be implemented before the wallet is ready for real funds.
No breach, CVE or published exploit found.
Blockstream's firmware flashed onto generic development boards for under fifty dollars.
DIY builds cannot pass the genuine check, have no secure boot, and the official guide warns explicitly about evil-maid attacks and tells you to control physical access at all times. The guide also advises against holding large sums on any hardware wallet.
No breach, CVE or published exploit found.
Two machines. An offline host holds an encrypted wallet file and signs partially signed transactions carried across by USB.
Private keys are written to disk on a general-purpose operating system, with everything that implies — swap, journaling filesystems, backups, firmware. The air-gap crossing is a USB stick.
No breach, CVE or published exploit found.
An offline machine holds an encrypted wallet file; unsigned transactions are carried to it by file and signed there.
Persistent encrypted key material on a general-purpose operating system, where your password is the whole defence. Electrum's own seed format is not BIP-39, which limits where it restores.
No breach, CVE or published exploit found.
An amnesic live operating system that runs from memory and leaves no trace on disk.
The documented Bitcoin workflow recommends turning on persistent storage to keep the wallet between sessions — so the amnesic operating system ends up carrying a persistent encrypted wallet. Without it, you re-enter the seed every session.
Tails does not claim protection against compromised firmware, which survives every reboot.
No breach, CVE or published exploit found.
Not a device — a memorisation scheme. A randomised grid of all BIP-39 words, plus a pattern of cells you choose and memorise. The grid can be stored openly; the pattern is the secret.
The grid carries enormous entropy but the pattern is the actual secret, and the site offers no guidance on how much entropy a human-chosen pattern carries. People choose lines, shapes and initials. The generator runs in a browser — the same failure class as the 2015 browser randomness incidents.
The seed must still be entered into some other device to spend. Memory decay is an unaddressed failure mode.
No breach, CVE or published exploit found.
Ships with no key. You copy 256KB of arbitrary data onto it and firmware derives a key from your data, a serial number, an internal nonce, a certified TRNG and USB timing jitter. It will not sign Bitcoin transactions. To spend, you physically break the seal and the private key appears on the drive.
Your key lives inside a vendor secure element from the moment it is created until you destroy the device. You contribute data, but closed firmware decides what to do with it — there is no measurement, no threshold and no refusal if what you supplied was predictable.
No breach, CVE or published exploit found.
A metal card with no chip and no firmware. The manufacturer generates the key in two halves before shipping: passphrase entropy in Las Vegas, the encrypted private key in Shanghai. You combine them via BIP38 the first time you use it. No BIP-39 seed phrase exists.
Two facilities you have never seen made your key and say they forgot it. Ballet's own documentation describes a QA process in which staff open sampled packages and handle both halves. There is no way to check any of it, and no way to generate another.
Ballet's founder, on Ballet's own blog, concedes that an evil Ballet could have booby-trapped the wallets and that no one can fully prove otherwise.
store.ballet.comA 2020 review found the private-key QR is a peel-off sticker rather than engraving, with no replacement offered if it comes away.
DecryptA laser-engraved steel plate. The manufacturer generates the key before shipping and engraves it by an automated process. The address is visible; the key sits under vinyl.
The company says the key came from an offline open-source engine, and never names it, links it, or publishes the process. There is no entropy detail, no public audit of generation, and no way to confirm your key is unique. You hold a piece of steel and a sentence.
No breach, CVE or published exploit found.
Several products here have never had a disclosed incident. We say so where it is true, and we do not imply otherwise. But an incident-free history describes the past, and it is offered by the same company that would have to tell you when it ends.
Every incident below is a matter of public record, cited to its source and dated. Where a company disputed a finding, fixed it, or disclosed it themselves, that is stated too. We cite them as history, not as a reason to be afraid.
