Using the Yubikey 4 as an OpenPGP smartcard with GnuPG: How is the user PIN and user passphrase secured?
In case a sophisticated attacker with physical access to the Yubikey 4 manages to physicaly extract the private-key under the microscope without knowing the user PIN and user passphrase:
What encryption (cipher, mode, hashing, etc.) is in place at this "last resort" to protect the private-key?
Is this very last cryptographic barrier made from GnuPG code or does the Yubikey manufacturer coded his own version?
- Since Yubikey 4 states its a compatible OpenPGP smartcard - does it mean it has the same PIN/passphrase protection as the G10 Smartcard?