Currently, in EOS Macsec, padding of partial keys internally prepends both the CAK and CKN hex strings with 0s to satisfy the requirement of Key Derivation Function.This feature allows users to configure the zero padding to either prepend or append the pre-shared CAK/CKN configured in mac security profile. In general, full length CAK/CKN are recommended to be configured. However, this CLI knob can be used in case of configuration of partial CAK/CKN results into issues with derived keys between the peers. Note that the CKN advertised in MACsec control frames will still be without any padding, even when partial CKN is configured.