Bitcoin developer says fear of self-hosting caused him to miss out on profits

German Bitcoin developers: Self-custody security concerns hinder holdings

German Bitcoin developer René Pickhardt said on August 6 that although he believed Bitcoin assets had potential to rise, concerns about self-custody security and key management prevented him from increasing holdings of more bitcoins.

Summary

Bitcoin developer Rene Pickhart said that self-custody security concerns prevented him from increasing his holdings in Bitcoin earlier. The Coldcard vulnerability makes seed phrases in some wallets predictable, exposing users to the risk of remote key recovery attacks. Galaxy Research estimates that approximately 1755 bitcoins were stolen in several rounds of attacks related to vulnerable wallets. Coinkite said that the patched firmware cannot repair the previously generated weak seeds, and users need migration funds. Adam Back believes that Bitcoin self-custody remains strong, but requires users to take on greater security responsibilities.

Pickhart wrote in a post: "Security and key management have always upset me," and described his decision as a risk management choice rather than a criticism of Bitcoin.

Bitcoin developers raise concerns about self-custody

His remarks came after the Coldcard hardware wallet incident, which re-examined the way self-custody tools generate private keys. Security research has linked vulnerable Coldcard firmware to predictable seed generation, while on-chain analysis cited by Galaxy Research estimates that approximately 1755 bitcoins were stolen in several rounds of attacks. The total amount of the loss is still under investigation.

Coldcard failure triggers review of Bitcoin key generation

The Coldcard problem involves the randomness used in wallet seed generation, rather than a flaw in the Bitcoin protocol itself. Block's Bitcoin security researchers have found that certain firmware configurations may bypass hardware randomness and rely instead on weaker software to generate entropy. This reduces the unpredictability of some seed phrases and may allow attackers to reconstruct private keys without physically touching the device.

Coinkite admitted firmware issues and released patches. However, the company warned that installing new firmware would not repair seeds generated under vulnerable conditions. Affected seed users must safely generate new seeds and transfer funds online. Citing a report from Galaxy Research, a report pointed out that more than 1000 bitcoins were stolen in a round of attacks on July 30, and subsequent rounds of attacks further pushed up estimated losses.

This incident clarifies the difference explained in the self-custody guide: Controlling private keys eliminates exchange counterparty risk, but transfers responsibility for key generation, backup, and recovery to the owner. Hardware wallets reduce the online attack surface, but rely on the randomness of firmware, hardware design, and security.

Pickhart: Security concerns outweigh Bitcoin's rising potential

Pickhart has long been engaged in Lightning Network routing and payment reliability research and was identified by BitcoinOptech as an open source Lightning Network developer and researcher working with OpenSats. In his 2026 paper, he proposed a mathematical framework for payment channel networks, focusing on liquidity and off-chain throughput.

In this context, his confession attracted attention because technical familiarity did not eliminate his custody concerns. Pickhart said that even correctly generated private keys face risks from storage, implementation errors and future computing advances. These concerns do not mean that properly implemented self-custody is inherently unsafe, but rather describe the operational burden that individual owners need to bear.

Adam Back, CEO of Blockstream, responded: "Having strong power to bearer cash means a huge responsibility of not losing the key." This time, the trade-off was captured: Bitcoin allows holders to control assets without a bank, but no central authority can reset lost private keys or revoke unauthorized valid transactions.

Coldcard losses intensify self-custody debate

Recent wallet security incidents provide the backdrop for the debate. Reports citing Galaxy Research said that in several rounds of attacks, approximately 1755 bitcoins were stolen from approximately 5000 wallets. Galaxy's estimate was previously low, and Coinkite also said that the full attribution and scope had not yet been determined, so the figure should be regarded as an evolving on-chain estimate rather than a final confirmation of loss.

This failure does not mean that all hardware wallets face the same flaws. Block said its products were not affected, and other manufacturers also explained their entropy-generation designs separately. The vulnerability follows the affected seed phrase, and even if it is imported into another wallet, simply replacing the hardware without creating a new key will not eliminate the underlying risk.

The Seed Phrase Security Guide explains why the recovery phrase is actually the master key for the wallet. If the generation link is weak, offline storage cannot recover the missing entropy afterwards. As a result, the Coldcard case shifted its focus from simply hiding the seed to verifying the security of its creation process.

What should Bitcoin holders focus on next

Coinkite's investigation, blockchain tracking, and the findings of any law enforcement agency will determine the ultimate size of Coldcard's losses. Users who create seeds on affected firmware should follow the manufacturer's remediation guidelines rather than believe that firmware updates alone can repair existing wallets.

Pickhart's comments are an exception for the broader Bitcoin market and do not prove that self-custody concerns are inhibiting adoption. However, this incident illustrates why usability and security are still closely linked. As hardware wallets become easier to purchase, manufacturers are under pressure to make key management both verifiable and easy to understand.

Pickhart's decision shows that confidence in the Bitcoin monetary theory does not automatically translate into comfort in the safety of bearer assets. Self-custody eliminates one type of intermediation risk but creates another set of responsibilities. Coldcard's failure makes this trade-off more difficult to ignore, especially for holders who are deciding whether direct ownership exceeds the operating burden of keeping their keys.