xref: /freebsd/share/man/man4/aesni.4 (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
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25.\" $FreeBSD$
26.\"
27.Dd September 26, 2017
28.Dt AESNI 4
29.Os
30.Sh NAME
31.Nm aesni
32.Nd "driver for the AES and SHA accelerator on x86 CPUs"
33.Sh SYNOPSIS
34To compile this driver into the kernel,
35place the following lines in your
36kernel configuration file:
37.Bd -ragged -offset indent
38.Cd "device crypto"
39.Cd "device cryptodev"
40.Cd "device aesni"
41.Ed
42.Pp
43Alternatively, to load the driver as a
44module at boot time, place the following line in
45.Xr loader.conf 5 :
46.Bd -literal -offset indent
47aesni_load="YES"
48.Ed
49.Sh DESCRIPTION
50Starting with Intel Westmere and AMD Bulldozer, some x86 processors implement a
51new set of instructions called AESNI.
52The set of six instructions accelerates the calculation of the key
53schedule for key lengths of 128, 192, and 256 of the Advanced
54Encryption Standard (AES) symmetric cipher, and provides a hardware
55implementation of the regular and the last encryption and decryption
56rounds.
57.Pp
58The processor capability is reported as AESNI in the Features2 line at boot.
59.Pp
60Starting with the Intel Goldmont and AMD Ryzen microarchitectures, some x86
61processors implement a new set of SHA instructions.
62The set of seven instructions accelerates the calculation of SHA1 and SHA256
63hashes.
64.Pp
65The processor capability is reported as SHA in the Structured Extended Features
66line at boot.
67.Pp
68The
69.Nm
70driver does not attach on systems that lack both CPU capabilities.
71On systems that support only one of AESNI or SHA extensions, the driver will
72attach and support that one function.
73.Pp
74The
75.Nm
76driver registers itself to accelerate AES and SHA operations for
77.Xr crypto 4 .
78Besides speed, the advantage of using the
79.Nm
80driver is that the AESNI operation
81is data-independent, thus eliminating some attack vectors based on
82measuring cache use and timings typically present in table-driven
83implementations.
84.Sh SEE ALSO
85.Xr crypt 3 ,
86.Xr crypto 4 ,
87.Xr intro 4 ,
88.Xr ipsec 4 ,
89.Xr padlock 4 ,
90.Xr random 4 ,
91.Xr crypto 9
92.Sh HISTORY
93The
94.Nm
95driver first appeared in
96.Fx 9.0 .
97SHA support was added in
98.Fx 12.0 .
99.Sh AUTHORS
100.An -nosplit
101The
102.Nm
103driver was written by
104.An Konstantin Belousov Aq Mt kib@FreeBSD.org
105and
106.An Conrad Meyer Aq Mt cem@FreeBSD.org .
107The key schedule calculation code was adopted from the sample provided
108by Intel and used in the analogous
109.Ox
110driver.
111The hash step intrinsics implementations were supplied by Intel.
112