Provide system-wide ring of blacklisted keys

modulename: blacklist.ko

and/or

blacklist_hashes.ko

and/or

blacklist_nohashes.ko

configname: CONFIG_SYSTEM_BLACKLIST_KEYRING

Linux Kernel Configuration
└─>Cryptographic API
└─>Certificates for signature checking
└─>Provide system-wide ring of blacklisted keys
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Provide a system keyring to which blacklisted keys can be added.
Keys in the keyring are considered entirely untrusted. Keys in this
keyring are used by the module signature checking to reject loading
of modules signed with a blacklisted key.

source code: