CONFIG_CRYPTO_XCTR (not configurable)

modulename: xctr.ko

configname: CONFIG_CRYPTO_XCTR

Linux Kernel Configuration
└─>Cryptographic API
└─>CRYPTO_XCTR
In linux kernel since version 6 (release Date: 2022-10-02)  
XCTR: XOR Counter mode. This blockcipher mode is a variant of CTR mode
using XORs and little-endian addition rather than big-endian arithmetic.
XCTR mode is used to implement HCTR2.

source code: