Bitcoin investors sharply increased transfers of their holdings after vulnerabilities were revealed in the Coldcard hardware wallet. The number of active Bitcoin addresses neared 1 million, hitting the highest level since last December. Data also showed a large amount of long-held coins moved.

Coinpost, a blockchain media outlet, reported on Sunday that on-chain analytics firm CryptoQuant found active Bitcoin addresses reached about 1 million on July 31, the highest level since Dec. 10, 2024.

A key feature of the rise was that sending addresses increased faster than receiving addresses. CryptoQuant analyst Julio Moreno said the number of active addresses surged in a single day from about 645,000 on July 30. He said the increase was driven mainly by an expansion in addresses used for transfers. New receiving addresses rose relatively little. Moreno said the pattern reflected investors urgently moving assets amid security concerns.

The large-scale movement follows a security defect in the Coldcard hardware wallet. Coldcard is a Bitcoin-only hardware wallet developed by Canadian firm Coinkite. It was confirmed that during a firmware integration process in March 2021, some devices used software-based pseudorandom numbers, rather than a hardware random number generator, to create seeds.

If the vulnerability is exploited, an attacker may be able to reproduce private keys without directly obtaining a device, it has been reported.

Losses also followed. Leaks occurred several times from July 30, and Galaxy Research estimated that as of Aug. 1 a total of 1,367 BTC, worth about $89 million, was stolen from about 4,585 addresses.

On-chain data also showed investors' urgent response. On July 31, exchange deposits involving transactions of under 10 BTC rose to about 7,300 BTC, the highest level since Feb. 6.

CryptoQuant analyst JA Martuun said about 77,402 BTC moved from UTXOs that had not moved for a long time after the vulnerability was disclosed. He interpreted it as a transfer to protect assets rather than a selling signal from long-term holders.

The pattern also contrasts with the FTX collapse in 2022. At the time, investors worried about exchange risk and moved assets from exchanges to personal wallets, but this time deposits into exchanges rose sharply. It is seen as reflecting moves to shift assets from self-custody wallets with confirmed vulnerabilities to safer storage methods.

The market views the incident as a case that affected broader Bitcoin on-chain activity beyond a defect in a specific hardware wallet. With a surge in active addresses, an increase in sending addresses and expanded exchange deposits all occurring at the same time, market attention is expected to remain on additional leak 규모 and trends in asset movement.