xref: /freebsd/share/man/man4/aesni.4 (revision 2008043f386721d58158e37e0d7e50df8095942d)
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25.Dd July 29, 2020
26.Dt AESNI 4
27.Os
28.Sh NAME
29.Nm aesni
30.Nd "driver for the AES and SHA accelerator on x86 CPUs"
31.Sh SYNOPSIS
32To compile this driver into the kernel,
33place the following lines in your
34kernel configuration file:
35.Bd -ragged -offset indent
36.Cd "device crypto"
37.Cd "device cryptodev"
38.Cd "device aesni"
39.Ed
40.Pp
41Alternatively, to load the driver as a
42module at boot time, place the following line in
43.Xr loader.conf 5 :
44.Bd -literal -offset indent
45aesni_load="YES"
46.Ed
47.Sh DESCRIPTION
48Starting with Intel Westmere and AMD Bulldozer, some x86 processors implement a
49new set of instructions called AESNI.
50The set of six instructions accelerates the calculation of the key
51schedule for key lengths of 128, 192, and 256 of the Advanced
52Encryption Standard (AES) symmetric cipher, and provides a hardware
53implementation of the regular and the last encryption and decryption
54rounds.
55.Pp
56The processor capability is reported as AESNI in the Features2 line at boot.
57.Pp
58Starting with the Intel Goldmont and AMD Ryzen microarchitectures, some x86
59processors implement a new set of SHA instructions.
60The set of seven instructions accelerates the calculation of SHA1 and SHA256
61hashes.
62.Pp
63The processor capability is reported as SHA in the Structured Extended Features
64line at boot.
65.Pp
66The
67.Nm
68driver does not attach on systems that lack both CPU capabilities.
69On systems that support only one of AESNI or SHA extensions, the driver will
70attach and support that one function.
71.Pp
72The
73.Nm
74driver registers itself to accelerate AES and SHA operations for
75.Xr crypto 4 .
76Besides speed, the advantage of using the
77.Nm
78driver is that the AESNI operation
79is data-independent, thus eliminating some attack vectors based on
80measuring cache use and timings typically present in table-driven
81implementations.
82.Sh SEE ALSO
83.Xr crypt 3 ,
84.Xr crypto 4 ,
85.Xr intro 4 ,
86.Xr ipsec 4 ,
87.Xr padlock 4 ,
88.Xr random 4 ,
89.Xr crypto 7 ,
90.Xr crypto 9
91.Sh HISTORY
92The
93.Nm
94driver first appeared in
95.Fx 9.0 .
96SHA support was added in
97.Fx 12.0 .
98.Sh AUTHORS
99.An -nosplit
100The
101.Nm
102driver was written by
103.An Konstantin Belousov Aq Mt kib@FreeBSD.org
104and
105.An Conrad Meyer Aq Mt cem@FreeBSD.org .
106The key schedule calculation code was adopted from the sample provided
107by Intel and used in the analogous
108.Ox
109driver.
110The hash step intrinsics implementations were supplied by Intel.
111