.\"	$OpenBSD: crypto.9,v 1.19 2002/07/16 06:31:57 angelos Exp $
.\"
.\" The author of this manual page is Angelos D. Keromytis (angelos@cis.upenn.edu)
.\"
.\" Copyright (c) 2000, 2001 Angelos D. Keromytis
.\"
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.\" is hereby granted, provided that this entire notice is included in
.\" all source code copies of any software which is or includes a copy or
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.\" IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
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.\" MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
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.\" $FreeBSD$
.\"
.Dd March 18, 2021
.Dt CRYPTO 9
.Os
.Sh NAME
.Nm crypto
.Nd API for cryptographic services in the kernel
.Sh SYNOPSIS
.In opencrypto/cryptodev.h
.Sh DESCRIPTION
.Nm
is a framework for in-kernel cryptography.
It permits in-kernel consumers to encrypt and decrypt data
and also enables userland applications to use cryptographic hardware
through the
.Pa /dev/crypto
device.
.Pp
.Nm
supports two modes of operation:
one mode for symmetric-keyed cryptographic requests and digest,
and a second mode for asymmetric-key requests and modular arithmetic.
.Ss Symmetric-Key Mode
Symmetric-key operations include encryption and decryption operations
using block and stream ciphers as well as computation and verification
of message authentication codes (MACs).
In this mode,
consumers allocate sessions to describe a transform as discussed in
.Xr crypto_session 9 .
Consumers then allocate request objects to describe each transformation
such as encrypting a network packet or decrypting a disk sector.
Requests are described in
.Xr crypto_request 9 .
.Pp
Device drivers are responsible for processing requests submitted by
consumers.
.Xr crypto_driver 9
describes the interfaces drivers use to register with the framework,
helper routines the framework provides to faciliate request processing,
and the interfaces drivers are required to provide.
.Ss Asymmetric-Key Mode
Assymteric-key operations do not use sessions.
Instead,
these operations perform individual mathematical operations using a set
of input and output parameters.
These operations are described in
.Xr crypto_asym 9 .
Drivers that support asymmetric operations use additional interfaces
described in
.Xr crypto_asym 9
in addition to the base interfaces described in
.Xr crypto_driver 9 .
.Ss Callbacks
Since the consumers may not be associated with a process, drivers may
not
.Xr sleep 9 .
The same holds for the framework.
Thus, a callback mechanism is used
to notify a consumer that a request has been completed (the
callback is specified by the consumer on a per-request basis).
The callback is invoked by the framework whether the request was
successfully completed or not.
Errors are reported to the callback function.
.Pp
Session initialization does not use callbacks and returns errors
synchronously.
.Ss Session Migration
For symmetric-key operations,
a specific error code,
.Er EAGAIN ,
is used to indicate that a session handle has changed and that the
request may be re-submitted immediately with the new session.
The consumer should update its saved copy of the session handle
to the value of
.Fa crp_session
so that future requests use the new session.
.Ss Supported Algorithms
More details on some algorithms may be found in
.Xr crypto 7 .
These algorithms are used for symmetric-mode operations.
Asymmetric-mode operations support operations described in
.Xr crypto_asym 9 .
.Pp
The following authentication algorithms are supported:
.Pp
.Bl -tag -offset indent -width CRYPTO_AES_CCM_CBC_MAC -compact
.It Dv CRYPTO_AES_CCM_CBC_MAC
.It Dv CRYPTO_AES_NIST_GMAC
.It Dv CRYPTO_BLAKE2B
.It Dv CRYPTO_BLAKE2S
.It Dv CRYPTO_NULL_HMAC
.It Dv CRYPTO_POLY1305
.It Dv CRYPTO_RIPEMD160
.It Dv CRYPTO_RIPEMD160_HMAC
.It Dv CRYPTO_SHA1
.It Dv CRYPTO_SHA1_HMAC
.It Dv CRYPTO_SHA2_224
.It Dv CRYPTO_SHA2_224_HMAC
.It Dv CRYPTO_SHA2_256
.It Dv CRYPTO_SHA2_256_HMAC
.It Dv CRYPTO_SHA2_384
.It Dv CRYPTO_SHA2_384_HMAC
.It Dv CRYPTO_SHA2_512
.It Dv CRYPTO_SHA2_512_HMAC
.El
.Pp
The following encryption algorithms are supported:
.Pp
.Bl -tag -offset indent -width CRYPTO_CAMELLIA_CBC -compact
.It Dv CRYPTO_AES_CBC
.It Dv CRYPTO_AES_ICM
.It Dv CRYPTO_AES_XTS
.It Dv CRYPTO_CAMELLIA_CBC
.It Dv CRYPTO_CHACHA20
.It Dv CRYPTO_NULL_CBC
.El
.Pp
The following authenticated encryption with additional data (AEAD)
algorithms are supported:
.Pp
.Bl -tag -offset indent -width CRYPTO_CHACHA20_POLY1305 -compact
.It Dv CRYPTO_AES_CCM_16
.It Dv CRYPTO_AES_NIST_GCM_16
.It Dv CRYPTO_CHACHA20_POLY1305
.El
.Pp
The following compression algorithms are supported:
.Pp
.Bl -tag -offset indent -width CRYPTO_DEFLATE_COMP -compact
.It Dv CRYPTO_DEFLATE_COMP
.El
.Sh FILES
.Bl -tag -width ".Pa sys/opencrypto/crypto.c"
.It Pa sys/opencrypto/crypto.c
most of the framework code
.El
.Sh SEE ALSO
.Xr crypto 4 ,
.Xr ipsec 4 ,
.Xr crypto 7 ,
.Xr crypto_asym 9 ,
.Xr crypto_driver 9 ,
.Xr crypto_request 9 ,
.Xr crypto_session 9 ,
.Xr sleep 9
.Sh HISTORY
The cryptographic framework first appeared in
.Ox 2.7
and was written by
.An Angelos D. Keromytis Aq Mt angelos@openbsd.org .
.Sh BUGS
The framework needs a mechanism for determining which driver is
best for a specific set of algorithms associated with a session.
Some type of benchmarking is in order here.