Knowledge Base Frequently Asked Questions YubiHSM What is the YubiHSM? Is the YubiHSM for symmetric encryption only? Is the YubiHSM security certified (FIPS 140 or similar)? Is the YubiHSM protected against physical intrusion? Are keys deleted on intrusion events? Is the internal CPU a designated security CPU or just an ordinary COTS one? Why is USB CDC used rather than a custom driver? The USB interface is only full-speed. Why not high-speed? Why is the internal YubiKey key storage set to just 1024 entries? Can the device firmware be upgraded via USB (otherwise known as DFU)?