Asymmetric public-key crypto algorithm subtype

modulename: public_key.ko

configname: CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE

Linux Kernel Configuration
└─>Cryptographic API
└─>Asymmetric (public-key cryptographic) key type
└─>Asymmetric public-key crypto algorithm subtype
In linux kernel since version 3.1 (release Date: 2011-10-24)  
This option provides support for asymmetric public key type handling.
If signature generation and/or verification are to be used,
appropriate hash algorithms (such as SHA-1) must be available.
ENOPKG will be reported if the requisite algorithm is unavailable.

source code: