HMAC (Keyed-Hash MAC)

modulename: hmac.ko

configname: CONFIG_CRYPTO_HMAC

Linux Kernel Configuration
└─>Cryptographic API
└─>Hashes, digests, and MACs
└─>HMAC (Keyed-Hash MAC)
In linux kernel since version 2.6.12  
HMAC (Keyed-Hash Message Authentication Code) (FIPS 198 and
RFC2104)

This is required for IPsec AH (XFRM_AH) and IPsec ESP (XFRM_ESP).

source code:
crypto/hmac.c

depends
CONFIG_CRYPTO

is selected by
CONFIG_RPCSEC_GSS_KRB5