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     aesni — driver for the AES accelerator on Intel CPUs


     To compile this driver into the kernel, place the following lines in your kernel
     configuration file:

           device crypto
           device aesni

     Alternatively, to load the driver as a module at boot time, place the following line in



     Starting with some models of Core i5/i7, Intel processors implement a new set of
     instructions called AESNI.  The set of six instructions accelerates the calculation of the
     key schedule for key lengths of 128, 192, and 256 of the Advanced Encryption Standard (AES)
     symmetric cipher, and provides a hardware implementation of the regular and the last
     encryption and decryption rounds.

     The processor capability is reported as AESNI in the Features2 line at boot.  The aesni
     driver does not attach on systems that lack the required CPU capability.

     The aesni driver registers itself to accelerate AES operations for crypto(4).  Besides
     speed, the advantage of using the aesni driver is that the AESNI operation is data-
     independent, thus eliminating some attack vectors based on measuring cache use and timings
     typically present in table-driven implementations.


     crypt(3), crypto(4), intro(4), ipsec(4), padlock(4), random(4), crypto(9)


     The aesni driver first appeared in FreeBSD 9.0.


     The aesni driver was written by Konstantin Belousov <>.  The key schedule
     calculation code was adopted from the sample provided by Intel and used in the analogous
     OpenBSD driver.