2 years ago
Bitcoin Magazine obtained exclusive entree to details astir the upcoming COLDCARD Mk4, the caller mentation of Canada-based Coinkite’s Bitcoin hardware wallet that improves upon the fashionable COLDCARD Mk3.
The main features of the caller exemplary see a USB-C connector, nary restrictions connected Bitcoin transaction size, accrued information with an other unafraid element, NFC integration, a descent cover, a USB virtual disk mode, and an extended “Trick PIN” optionality.
The beforehand and backmost of Coinkite's upcoming hardware wallet, the COLDCARD Mk4. Photo courtesy of Coinkite.
Near-Field Communication (NFC)
In the connections front, the idiosyncratic tin opt into utilizing NFC with the Mk4 by enabling it successful the device’s settings arsenic the diagnostic volition travel disabled by default. Once turned on, NFC volition alteration the COLDCARD to travel adjacent a compatible instrumentality to motion a transaction oregon a message, co-sign successful a multisig setup, oregon stock accusation from the device’s MicroSD paper similar a outgo code oregon an extended nationalist key, a partially-signed Bitcoin transaction (PSBT), a substance file, oregon a transaction file.
Coinkite laminitis NVK told Bitcoin Magazine that the extremity with NFC is to little cost, amended UX, and further adoption.
“Imagine hardware wallets being capable to conscionable tap-to-pay,” helium said.
Although QR codes person precocious go fashionable successful immoderate hardware wallets, NVK said they haven’t been adopted successful the larger outgo industries due to the fact that they person highly debased information bandwidth, are much analyzable and not quality readable, and necessitate much costly hardware.
“This diagnostic was added to amended phone-wallet UX arsenic each modern phones person NFC, free, already sitting unused,” NVK said. “NFC volition beryllium disposable to each COLDCARD functions we are capable to nonstop oregon person data, conscionable similar the SD paper oregon USB cable.”
In summation to requiring NFC to beryllium turned connected for usage, NVK told Bitcoin Magazine that the Mk4 volition besides alteration the idiosyncratic to permanently disable the diagnostic by scratching a PCB hint exposed connected the MicroSD opening.
An Extra Secure Element
While erstwhile versions of the COLDCARD had a azygous secure element (SE), Mk4 brings a 2nd SE to found a much robust information exemplary for the user’s backstage keys and suppress imaginable azygous points of failure. Moreover, the information that the 2nd SE is from a antithetic vendor further protects the idiosyncratic from immoderate unexpected bugs oregon issues with a circumstantial SE design.
An attacker would request to afloat compromise the 2 unafraid elements and the main microcontroller (MCU) earlier being capable to extract effect words from the COLDCARD Mk4 arsenic the instrumentality present distributes the encryption cardinal among the 3 components. Additionally, adjacent if each 3 components are compromised, the device’s PIN codification would inactive beryllium required.
‘Trick PINs’ And Additional Improvements
Mk4 besides allows the idiosyncratic to acceptable up aggregate “Trick PINs.” While the existent PIN unlocks the instrumentality and enables wallet functions, Trick PIN codes tin exert alternate functionality specified arsenic unlocking a duress wallet, triggering a agelong login delay, oregon bricking oregon blanking the COLDCARD.
These PINs are utile successful antithetic scenarios, but they tin often travel successful useful successful a carnal onslaught wherever the idiosyncratic is coerced into unlocking their COLDCARD. For instance, the idiosyncratic tin conscionable usage a Trick PIN for unlocking a duress wallet for plausible deniability. Alternatively, successful a much utmost scenario, the idiosyncratic tin benignant successful a Trick PIN that wipes the COLDCARD cleanable and past bricks it, making it unusable.
Additional improvements brought by Mk4 implicit Mk3 see faster booting; a 120 Mhz CPU, up from 80 Mhz; maximum abstraction for settings – present 512 KB, up from 4 KB; much multisig wallet possibilities; firmware upgrade present takes 15 seconds, down from 2 minutes; 216 bytes of caller unafraid retention alongside main effect phrase; a flashing airy indicating erstwhile the USB transportation is successful use; a USB disk emulation for elemental usage with web browsers and different PSBT sources; and a doubled flash representation for firmware, among different updates.
Mk4’s motorboat day is yet to beryllium determined, but the instrumentality is disposable for pre-order astatine the Coinkite store.
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