Hunting Down the Coldcard Hacker. Wave 1 Thief May Be Known to FBI

The critical change entered the codebase on March 1, 2021, in a commit titled “First pass w/ libNgU” (b18723dd). That commit replaced remaining Trezor-derived cryptography and BIP-39 code with a new library, libngu, and rewired seed generation. The intended result was that the call for randomness resolved to the STM32 hardware’s true random number generator. However, the bug redirected the call to MicroPython’s software Yasmarang PRNG instead, resulting in an effective entropy collapse to roughly 40 bits on older models and around 72 bits on newer ones. That meant the Bitocin private keys generated were effectively guessable by modern computing hardware. This swap of cryptographic libraries was pushed to the codebase by Doc-Hex, also known as Peter Gray, the Chief Technical Officer of Coinkite. 

The move was arguably driven by licensing pressure, according to Foundation Devices CEO and founder Zach Herbert, though Coinkite has denied this as a primary motivation for the code change, saying, “COLDCARD had to make this change to move to libsecp256k1; the license change is irrelevant to this. libsecp256k1 is the standard library used by Bitcoin Core.”

Coldcard had been using Trezor-derived code under the GPLv3 open source license. After Foundation Devices forked related material, Coinkite sought to move remaining components to a more restrictive MIT + Commons Clause arrangement that limited commercial reuse. The rewrite was large and carried complex engineering goals; it was this integration that arguably left the silent failure in the entropy path.

Skepticism about the migration away from the Trezor crypto library emerged as early as April 7, 2021, by a member of the Coinkite Telegram group, who wrote: “do we really want to replace the many-years-old TrezorCrypto code that has been heavily scrutinized by white hatters like Johoe and penetration tested by wallet.fail”, adding “switch may be a talented pseudonymous coder, but their commit history sucks.” The criticism, however, was insufficient and quickly waved away by NVK, who criticized the Trezor library as a “shitcoin shitshow.” Ironically, sharing that codebase with the broader crypto market, under an open license meant that Trezor’s crypto library had much deeper code review than Libngu would ever get, even years later. 

Switch and Peter Gray aka Doc-Hex

The swap of cryptographic libraries that introduced the bug was pushed to the codebase by Doc-Hex, the Chief Technical Officer of Coinkite, also known as Peter D. Gray. He replaced the GPLv3 Trezor cryptography library with Libngu, a little-known codebase created by so-called “Switch”, a nym that, up until the creation of Libngu, had no obvious previous history. The Switch account appeared on X on August 3, 2019 with a mention of DEFCON, the international hacker’s conference, an event normally attended by cybersecurity engineers of all kinds. 

On October 16, 2020, Switch thanked Doc-Hex on X for merging his code; “Thanks for merge @DocHex … I’m making yet another bitcoin library. Could be useful on @COLDCARDwallet someday.” A few days later, Switch tweeted out a link to Libngu, proud to have built a “useful thing.”  

However, here is where it gets weird. According to research by Bitcoin core contributor James O’Beirne, Switch and Peter D. Gray have signed code commits with the same GPG keys. O’Beirne demonstrated through GPG commit signatures that dozens of commits authored as switck were signed with the personal key of Peter D. Gray, Coinkite co-founder and CTO, who also operates as DocHex. Zach Herbert also claimed that phone numbers ending in the same two digits were tied to both the DocHex and switck X accounts (post). Additional researchers pointed to matching DNS registration patterns.

Neither Gray nor Coinkite has publicly addressed the GPG-signature findings as of this writing, and they did not respond when asked to comment on the topic. The Switch account is still active to this day, having merged code changes to Libngu as recently as August 17th, 2026.

Many in the Bitcoin industry are taking this as some sort of tangential evidence of wrongdoing. Why go out of your way to create a nym just for a particular cryptography library? This has been taken as some kind of evidence of malintent; however, a deeper analysis begs to differ. Had Gray really intended to rug Coldcard users with this RNG bug, would he really have been signing commits with his personal GPG key? Could someone be so cunning that they would hide a bug for years, waiting for its adoption to spread; yet at the same time forget to create a dedicated GPG signature for the throwaway nym? I don’t think that tracks. 

It is more likely that this was a random identity created at DEFCON by Gray, probably in a random bout of paranoia. An identity which he continued to use for certain projects over the years. Pseudonymous identities are not unusual in Bitcoin developer circles after all. Satoshi himself remains the most famous example. And so on its own, this connection between Gray and Switch arguably does not amount to much in the hunt for the Coldcard hacker.

MicroPython Contributors

A handful of other open source developers have also been recently identified as having touched or influenced code that played a role in the Coldcard RNG bug. 

Data Analyst LaurentMT has examined the MicroPython side of the RNG path. MicroPython is a lean and open-source implementation of Python 3, designed to run on microcontrollers and resource-constrained computers. The Coldcard firmware ultimately called MicroPython’s Yasmarang pseudo-random number generator (PRNG) fallback as a result of the bug, leading to low-entropy generation. 

The code changes to the PRNG logic in MicroPython began on August 20, 2020, with issue (#6347) opened on GitHub by a user named ‘mirko’. He complained that his ESP32 hardware was always returning the same result when calling the ‘random.choice()’ function in the code in a certain way. Mirko expected random results instead. The GitHub issue logs a discussion over the following months about the proper way to handle the related logic and expected behavior, which Mirko revealed to have a counterintuitive design. 

Laurent points out that “robert-hh initialized a [Pull Request] implementing the PRNG seeding change” on August 22, 2020. Dpgeorge, a maintainer of MicroPython, later on October 29, 2020, merged a slightly modified version of that pull request to the master repository, implementing “the (UID+SysTick+RTC) to address some limitations in robert-hh’s solution.”

The changes to this critical RNG-related code were thus on the master repository of MicroPython when Coldcard forked it to be used by Libngu, yet before MicroPython had made an official new version release of the library. Apparently, it is considered risky to build on top of the master version of a software repository, which is likely to be evolving with code changes, rather than build on top of an official, stable release version. The new release of MicroPython did not come until February 3, 2021, with version v1.14. To top it off, the RNG logic change was only briefly mentioned in the release announcement, saying “the urandom module will randomize its seed on import on stm32, esp8266, esp32 and rp2 ports.”  

In an interview with Bitcoin Magazine, Laurent concluded in no ambiguous terms that “without this modification the bug in Coldcard code would have been immediately detected.” Commenting on the series of events that led to the bug, he also said that “there are a lot of ‘coincidences’ in this timeline,” adding that “while they don’t prove anything, I don’t see how an official investigation may completely ignore them.”

It is important to note that there is no evidence any of the developers mentioned above were intentionally trying to introduce the Coldcard RNG bug with these changes, and ultimately, it is Coinkite, the hardware wallet company, that is responsible for their implementation of the critical code. MicroPython is a large, widely used open-source project. Nevertheless, there are likely many lessons to be learned from what we might as well call — for the time being anyway — a tragic comedy of errors. 

Why an Inside Job Appears Unlikely

Several factors cut against a deliberate, long-planned insider retirement attack. The ‘switck’ identity was poorly compartmentalized; the shared GPG key and other overlaps made attribution to Doc-Hex aka Peter Gray, relatively straightforward once researchers looked. The account had been largely abandoned for years. The MicroPython contributors operate in the open on a high-visibility project.

Hodlonaut’s Citadel21 investigation and other technical reviews find no clear evidence that the entropy failure was intentional. Engineer Alekos Filini’s technical report on the bug explicitly tracks the technical facts, stating that “My goal is to purely present facts and NOT make any conclusions.” Wizardsardine detailed on their Technical autopsy multiple failed safeguards and describes the failure as sitting “across a submodule boundary, which is precisely where reviewers stop looking.” 

Steven Geller’s technical deep dive on the topic did not make any strong claims either way on the matter. DK27ss proof-of-concept reconstruction of the bug describes the issue as “a chain of four flaws, each harmless in appearance.” 

If the drains had been a classic insider retirement attack, or a long con as some might call it, the conversation today would be quite different. The last time we saw a major long con hack in the Bitcoin industry was probably QuadrigaCX, a centralized Canadian exchange whose founder, Gerald Cotten, was reported “dead in India” in 2018 amid mysterious circumstances, not long after the missing funds were discovered. The founders are accused by the Ontario Securities Commission of having misappropriated the exchange users’ deposits totaling almost 170 million CAD, over many years, before disappearing. 

Instead, Coinkite’s leadership remains publicly active, responding to the incident, shipping patched firmware, assisting user migrations, and engaging on the technical details. Coinkite’s founders and operators are fairly well known and are still operating the company as of the time of writing; they have not disappeared at the same time as the funds went missing.

Meanwhile, the wave 1 funds, totaling over 1000 BTC, are still collected in three addresses, watched by hundreds of engineers and likely law enforcement such as the FBI. Were Coinkite trying to do a 5D chess-style retirement attack, they would have been far more careful in their theft of the coins. They would not have pooled them all to a handful of addresses that are easy to track, and its founders would probably be ‘mysteriously dead in India.’

While there are no conclusions and investigations will likely be ongoing for years, so far, evidence points to a cultural failure in the Bitcoin maximalist and self-custody community, a failure to broadly educate the users and influencers about good or bad etiquette in open-source culture, and frankly, arrogance on the part of Coinkite OG’s who, in hindsight, were overconfident about their own capabilities.