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FIDO_DEV_SET_PIN(3) Library Functions Manual FIDO_DEV_SET_PIN(3)


fido_dev_set_pin, fido_dev_get_retry_count, fido_dev_reset
FIDO 2 device management functions


#include <fido.h>

fido_dev_set_pin(fido_dev_t *dev, const char *pin, const char *oldpin);

fido_dev_get_retry_count(fido_dev_t *dev, int *retries);

fido_dev_reset(fido_dev_t *dev);


The fido_dev_set_pin() function sets the PIN of device dev to pin, where pin is a NUL-terminated UTF-8 string. If oldpin is not NULL, the device's PIN is changed from oldpin to pin, where pin and oldpin are NUL-terminated UTF-8 strings.

The fido_dev_get_retry_count() function fills retries with the number of PIN retries left in dev before lock-out, where retries is an addressable pointer.

The fido_dev_reset() function performs a reset on dev, resetting the device's PIN and erasing credentials stored on the device.

Please note that fido_dev_set_pin(), fido_dev_get_retry_count(), and fido_dev_reset() are synchronous and will block if necessary.


The error codes returned by fido_dev_set_pin(), fido_dev_get_retry_count(), and fido_dev_reset() are defined in <fido/err.h>. On success, FIDO_OK is returned.


Regarding fido_dev_reset(), the actual user-flow to perform a reset is outside the scope of the FIDO2 specification, and may therefore vary depending on the authenticator. Yubico authenticators will return FIDO_ERR_NOT_ALLOWED if a reset is issued later than 5 seconds after power-up, and FIDO_ERR_ACTION_TIMEOUT if the user fails to confirm the reset by touching the key within 30 seconds.
May 25, 2018 Linux 4.19.0-12-amd64