Key overwrite feature allows to overwrite old pairing key
records when key storage is full and a new pairing request occurs,
or new keys are distributed. If enabled when key storage is full and
a keys storage slot is requested, the oldest keys added will be
removed. So new devices can be paired with no limitations and no need
to determine, which devices should be unpaired to free key storage
space explicitly in application. To enable the feature set
CONFIG_BT_KEYS_OVERWRITE_OLDEST=y.
Oldest keys are determined by minimum value of up-counting aging
counter. If you set CONFIG_BT_KEYS_SAVE_AGING_COUNTER_ON_PAIRING=y
aging counter values will be updated each time the secure connection
is established. This might increase flash wear out if at least two
secure connections are established and shut down periodically. When
the option disabled aging counter is still updated on each new secure
connection, but not stored to flash.
Signed-off-by: Sergiy Nikolayenko <sergiy_nikolayenko@jabil.com>
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