Coldcard wallet maker requires users to add entropy by themselves, causing Bitcoin to be stolen due

Firmware 5.6.1 requires users to provide their own random number for each new seed. Previously, a major Bitcoin vulnerability was exposed.

Coinkite pushed firmware version 5.6.1 for its Coldcard hardware wallet. This update requires users to provide their own entropy value when creating each new seed on their device. Previously, the generation of seeds mainly relied on the built-in random number generator in the wallet.

This change stems from a report of a seed-related vulnerability related to a major Bitcoin theft. According to CryptoPotato, the loss was approximately US$100 million; The Cryptomist EN gave a figure of US$112 million. The two reports describe the same incident, but the specific total loss has not been completely unified among different reports.

Seed generation is the foundation of a self-managed wallet. The mnemonic words (usually 12 or 24 words) encode the private key that controls user funds. If the randomness behind the seed is predictable, weak, or corrupted in any way, an attacker can theoretically reconstruct the private key and empty the associated wallet. This risk is at the heart of the vulnerability currently under review.

Forcing users to provide entropy is a long-recommended mitigation measure by security researchers. It usually involves methods such as rolling dice, taking images with a camera, or other manual random sources. These inputs will be combined with, rather than replacing, the randomness built into the device. The goal is to reduce reliance on any single random source, including sources that can go wrong due to firmware vulnerabilities or supply chain attacks.

Hardware wallets are advertised as a safer option than exchange hosting because the private key never leaves the device. This reputation depends largely on the integrity of the random number generation process during the setup process. Defects at this stage can undermine the core security promise of cold storage, no matter how well the device protects the key later.

This incident exacerbates a recurring pattern in the field of cryptocurrency security. Losses related to exchange hacking and smart contract vulnerabilities are more common. While rare, vulnerabilities in hardware wallets or key generation can be more damaging because they quietly expose funds that owners believe are fully safe. Users who have generated seeds on affected firmware versions may need to check Coinkite's official guidelines to determine whether it is necessary to migrate to a newly generated seed.

In existing reports, Coinkite has not commented directly on the specific technical root cause of the vulnerability. However, changes to the firmware itself indicate that the company believes the existing entropy process is insufficient to provide independent security. Asking users to provide input is used as a direct response to reported vulnerabilities.

Market impact

The direct impact may be concentrated on Coldcard users and the broader hardware wallet area in the self-managed market. A review of seed generation practices may prompt other hardware wallet makers to review or strengthen their own entropy implementations.

For the broader cryptocurrency market, the incident strengthens the ongoing debate about custody risks. Institutional and retail investors weighing self-custody versus exchange-held assets may include this event in their risk assessments. There is no price or transaction data in available reports directly linked to this event, so any broader market reaction remains to be confirmed.

This firmware update reflects a direct response to reported seed vulnerabilities, and the scale of the related losses still varies among different channels. Coldcard users are advised to update firmware and consult Coinkite's official guidelines for future seed processing.

FAQs

What is Coldcard? Coldcard is a hardware wallet made by Coinkite that is designed to store Bitcoin private keys offline for self-custody.

What does "user entropy" mean here? User entropy refers to the randomness of individual manual contributions, such as dice rolling or camera input, which is combined with the randomness built into the device when generating new seeds.

How many bitcoins were reported lost in the bitcoin theft incidents related to this update? Reports have been mixed, with CryptoPotato claiming losses of approximately US$100 million, while The Cryptomist EN claiming losses of US$112 million.

Do existing Coldcard users need to take action? Users who generated seeds before this update are advised to check Coinkite's official guidelines to determine whether to recommend re-generating seeds.