Understanding The COLDCARD Mk4 Security Model and Secure Element Use
A step by step overview of how the Coldcard hardware wallet secures bitcoin keys.
By using this security architecture, you can rest easy knowing that it is currently close to impossible to breach the COLDCARD Mk4. The use of two secure elements and a microcontroller for splitting secrets that are only accessible after going through extensive cryptographic handshakes greatly reduces the device’s attack surface.
Although the secure elements used are closed source, the code that runs on the device isn’t. Even if one of both of the secure elements were to be compromised, however unlikely that may be, your private key remains safe.