CTR (Counter)

modulename: ctr.ko

configname: CONFIG_CRYPTO_CTR

Linux Kernel Configuration
└─>Cryptographic API
└─>Length-preserving ciphers and modes
└─>CTR (Counter)
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
CTR (Counter) mode (NIST SP800-38A)

source code: