Bitcoin Magazine

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

Law enforcement may already know who emptied more than a thousand Bitcoin from Coldcard wallets in the first and largest wave of the July 2026 drains. Block’s investigation believes they traced the attacker’s on-chain sweeps to a paid account at a major blockchain data provider whose internal logs matched the theft pattern with “extraordinary specificity.” 

PSA: The attack is ongoing, targeting weak private keys generated on devices as old as the MK2 with firmware 4.0.1 onwards. If you may have one, double-check and move funds asap. See Coinkite advisory and status page.

The coins from that wave—1,082.65 BTC—still sit untouched in the attacker’s address, leaving hope that a clawback may be possible to the victims and rightful owners of that first wave of stolen bitcoin. The question now is, who is the hacker and whether the same lead points to a sophisticated outsider, or whether the five-year-old entropy bug that made the theft possible was something closer to the insider “retirement attack” Coinkite itself once warned about.

What We Know

On July 30, 2026, an attacker began systematically draining Bitcoin from Coldcard hardware wallets that had generated seeds under vulnerable firmware, a bug that was undiscovered for years. The first and largest wave alone moved 1,082.65 BTC. Subsequent waves followed, with estimates over 2k BTC. Alex Thorn at Galaxy Research has tracked the activity through a combination of on-chain pattern analysis and voluntary victim reports. As of early August, confirmed and estimated losses across multiple waves exceeded 1,800 BTC from more than 5,000 addresses, though exact final totals continue to be refined as new reports arrive. In dollar terms, roughly $118 million has been confirmed stolen.

Thorn has publicly discussed the possibility that law enforcement already holds a concrete lead on the operator behind the largest tranche. In a Bitcoin Policy Institute segment hosted on the Bitcoin Magazine YouTube channel, Thorn stated: “Wave one’s identity, attacker identity, may be known to law enforcement.” He added that Wave 1 remains the biggest single chunk identified so far, with the coins still sitting in the attacker’s address, and noted that Wave 2’s pattern looks similar enough that it could involve the same actor. Wave 2 adds another 76 or so bitcoin to the total. 

The primary source for the claim that the hacker’s identity might be known is Clay Garrett, engineering lead at Block working on Bitkey. On July 31, 2026, Garrett posted the findings from Block’s investigation:

“During our investigation of the Coldcard drain yesterday, we identified an unusual pattern in the sweeps. That pattern led us to a hypothesis that has since been confirmed: the operator used a paid account at a well-known blockchain-services provider to query the source addresses and perform other related activity during the sweeps.”

“We contacted the provider directly. Their internal logs matched the suspected workflow with extraordinary specificity, including the number, timing and sequence of requests. The provider was supplying its standard services in response to requests that did not reveal their broader purpose. We have seen no evidence that the provider knowingly participated in or facilitated the suspected theft.” Garrett said, and added that; “We are sharing the relevant information with the appropriate authorities. We will provide further updates when doing so will not interfere with the investigation.”

Thorn and others have noted that later, smaller waves show different operational patterns—some rapid, opportunistic drains followed by quick laundering—suggesting additional actors may have reverse-engineered the same weak seed space after the initial public disclosure. Self-reported confirmed drains appear to have slowed sharply after August 6, though many potentially vulnerable seeds generated on the affected firmware between 2021 and the July 2026 patch remain at risk until users migrate.

A Retirement Attack?

The nature of the failure has led to conspiracy theories about insider attacks that Coinkite itself once discussed publicly. In October 2021, the official COLDCARD account defined a “retirement attack” as the scenario “when the project makers could have a ‘bug’ in the entropy generation for later retrieval.”

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.”

Source: BitcoinMagazine