Cold Storage Flaws Exposed: AI-Powered Attacks Threaten Bitcoin Security

A recent technical disclosure by Coinkite highlights the vulnerabilities in Bitcoin's cold storage architecture. The report reveals that even when private keys are kept offline, they can still be compromised due to weaknesses in the surrounding software and hardware.

The issue lies in the way entropy is generated during seed phrase creation. Coinkite found that a 2021 integration change caused wallet seed generation to use MicroPython software instead of the intended hardware random-number path, compromising security. However, new firmware has been implemented to prevent this issue in future generations.

A more significant threat to Bitcoin's security comes from AI-powered attacks. Coinkite also suggested that AI could potentially be used to discover vulnerabilities in the custody stack. In fact, researchers have demonstrated methods for encoding seed material into valid transaction signatures, which can travel through the normal transaction path without being detected.

The Dark Skippy researchers successfully encoded a 256-bit seed in 10 valid ECDSA signatures, while another project built an end-to-end backdoored wallet on Bitcoin testnet and leaked a 256-bit seed. These experiments highlight the danger of covert use: a transaction can satisfy Bitcoin's rules while the device creating it acts against its owner.