trezor-firmware/core/src/storage/fido2.py

# FIDO2 keys that should be generated once per power-up
# https://fidoalliance.org/specs/fido-v2.0-ps-20190130/fido-client-to-authenticator-protocol-v2.0-ps-20190130.html#authenticator-power-up-configuration
# While we could safely generate these keys per-wipe and save them in sessionless cache,
# this drags down the performance of our test suite.

# We want to avoid importing `trezor.crypto.curve` because that would needlessly pollute
# our RAM space, while in the end importing the symbol from `trezorcrypto` directly anyway
from trezorcrypto import nist256p1

# the authenticatorKeyAgreementKey used for ECDH in authenticatorClientPIN getKeyAgreement.
KEY_AGREEMENT_PRIVKEY = nist256p1.generate_secret()
KEY_AGREEMENT_PUBKEY = nist256p1.publickey(KEY_AGREEMENT_PRIVKEY, False)
refactor(core/webauthn): make sure KEY_AGREEMENT_*KEY is generated once per power-up This is what the spec recommends and it has been the case before workflow-restarts, when `apps.webauthn.fido2` was imported exactly once per lifetime. With workflow-restarts, `fido2` is being imported repeatedly and the keys regenerated. This does not seem to be a problem per the spec -- a FIDO workflow will retain the same keys, and non-FIDO workflows can be seen as unplugs/replugs as far as the FIDO functionality is concerned. However, regenerating the keys is slow, which is a problem for the hardware-based unit tests. We can avoid the slowness by returning to the spec-mandated behavior and generating once per power-up. 2021-04-08 10:43:28 +00:00			`# FIDO2 keys that should be generated once per power-up`
			`# https://fidoalliance.org/specs/fido-v2.0-ps-20190130/fido-client-to-authenticator-protocol-v2.0-ps-20190130.html#authenticator-power-up-configuration`
			`# While we could safely generate these keys per-wipe and save them in sessionless cache,`
			`# this drags down the performance of our test suite.`

			# We want to avoid importing `trezor.crypto.curve` because that would needlessly pollute
			# our RAM space, while in the end importing the symbol from `trezorcrypto` directly anyway
			`from trezorcrypto import nist256p1`

			`# the authenticatorKeyAgreementKey used for ECDH in authenticatorClientPIN getKeyAgreement.`
			`KEY_AGREEMENT_PRIVKEY = nist256p1.generate_secret()`
			`KEY_AGREEMENT_PUBKEY = nist256p1.publickey(KEY_AGREEMENT_PRIVKEY, False)`