Extensions
| Feature | Entry points | Application concern |
|---|---|---|
hmac-secret |
fido_assert_set_extensions(),
fido_assert_set_hmac_salt()
|
Provide one or two salts; read derived output from assertion accessors. |
credProtect |
fido_cred_set_prot()
|
Credential protection policy is set during registration. |
largeBlob |
fido_dev_largeblob_get()
/
fido_dev_largeblob_set()
|
Storage capability and authentication requirements vary. |
credBlob |
fido_cred_set_blob()
|
Small per-credential data, where supported. |
For hmac-secret, enable FIDO_EXT_HMAC_SECRET on the assertion
and set its salt before fido_dev_get_assert(). Retrieve output via
fido_assert_hmac_secret_ptr()
and the matching length accessor. The output
can differ depending on whether user verification was performed.
Extension support depends on the authenticator and operation. Unsupported requests return an error.