[src/uebayasi-xip]: src/share/man/man4 Leave space as usual after Nm.

[wiz <wiz%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/237d124f6fa3
branches:  uebayasi-xip
changeset: 751665:237d124f6fa3
user:      wiz <wiz%NetBSD.org@localhost>
date:      Thu Apr 15 09:56:57 2010 +0000

description:
Leave space as usual after Nm.

diffstat:

 share/man/man4/cgd.4 |  194 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 194 insertions(+), 0 deletions(-)

diffs (198 lines):

diff -r 0d0aa5dfc7ed -r 237d124f6fa3 share/man/man4/cgd.4
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+++ b/share/man/man4/cgd.4      Thu Apr 15 09:56:57 2010 +0000
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+.\" $NetBSD: cgd.4,v 1.16.2.2 2010/04/15 09:56:57 wiz Exp $
+.\"
+.\" Copyright (c) 2002, 2003 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Roland C. Dowdeswell.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd April 15, 2010
+.Dt CGD 4
+.Os
+.Sh NAME
+.Nm cgd
+.Nd cryptographic disk driver
+.Sh SYNOPSIS
+.Cd "pseudo-device cgd" Op Ar count
+.Sh DESCRIPTION
+The
+.Nm
+driver provides the capability of encrypting blocks on their way
+to and from a disk or partition.
+.Pp
+In order to compile support for the
+.Nm
+into your kernel, you must add the driver to your kernel configuration
+file.
+To do this, add a line similar to:
+.Bd -unfilled -offset indent
+pseudo-device   cgd     4       # cryptographic disk driver
+.Ed
+.Pp
+The count argument defines how many
+.Nm
+devices may be configured at a time.
+.Ss Encryption Algorithms
+Currently the following cryptographic algorithms are supported:
+.Bl -tag -width indentxxxxxxx
+.It Ic aes-cbc
+.Tn AES
+in
+.Tn CBC
+mode.
+.Tn AES
+uses a 128 bit blocksize and can accept keys of length 128, 192, or 256.
+The default key length is 128.
+.It Ic 3des-cbc
+Triple
+.Tn DES
+in
+.Tn CBC
+mode.
+Triple
+.Tn DES
+uses a 64 bit blocksize and is performed in
+.Tn EDE3
+mode with a 168 bit key.
+The key passed to the kernel is 192 bits but the parity bits are ignored.
+.It Ic blowfish-cbc
+Blowfish in
+.Tn CBC
+mode.
+Blowfish uses a 64 bit blocksize and can accept keys between 40 and
+448 bits in multiples of 8.
+It is strongly encouraged that keys be at least 128 bits long.
+There are no performance advantages of using shorter keys.
+The default key length is 128 bits.
+.El
+.Ss IV Methods
+Currently, the following
+.Tn IV
+Methods are supported:
+.Bl -tag -width encblkno1
+.It Ic encblkno1
+This method  encrypts the block number of the physical disk block once with
+the cipher and key provided and uses the result as the
+.Tn IV
+for
+.Tn CBC
+mode.
+This method should ensure that each block has a different
+.Tn IV
+and that the
+.Tn IV
+is reasonably unpredictable.
+This is the default method used by
+.Xr cgdconfig 8
+when configuring a new
+.Nm .
+.It Ic encblkno8
+This is the original
+.Tn IV
+method used by
+.Nm
+and provided for backward compatibility.
+It repeatedly encrypts the block number of the physical disk block
+eight times and uses the result as the
+.Tn IV
+for
+.Tn CBC
+mode.
+This method should ensure that each block has a different
+.Tn IV
+and that the
+.Tn IV
+is reasonably unpredictable.
+The eightfold encryption was not intended and causes a notable
+performance loss with little (if any) increase in security over a
+single encryption.
+.El
+.Ss IOCTLS
+A
+.Nm
+responds to all of the standard disk
+.Xr ioctl 2
+calls defined in
+.Xr sd 4 ,
+and also defines the following:
+.Bl -tag -width CGDIOCSET -offset indent
+.It Dv CGDIOCSET
+Configure the
+.Nm .
+This
+.Xr ioctl 2
+sets up the encryption parameters and points the
+.Nm
+at the underlying disk.
+.It Dv CGDIOCCLR
+Unconfigure the
+.Nm .
+.El
+.Pp
+These
+.Xr ioctl 2 Ns 's
+and their associated data structures are defined in
+.In dev/cgdvar.h
+header.
+.Sh WARNINGS
+It goes without saying that if you forget the passphrase that you used
+to configure a
+.Nm ,
+then you have irrevocably lost all of the data on the disk.
+Please ensure that you are using an appropriate backup strategy.
+.Sh FILES
+.Bl -tag -width indentxxxxxxxxxxx
+.It /dev/{,r}cgd*
+.Nm
+device special files.
+.El
+.Sh SEE ALSO
+.Xr config 1 ,
+.Xr ioctl 2 ,
+.Xr sd 4 ,
+.Xr cgdconfig 8 ,
+.Xr MAKEDEV 8
+.Rs
+.%A Roland C. Dowdeswell
+.%A John Ioannidis
+.%T The CryptoGraphic Disk Driver
+.%I USENIX Association
+.%B Proceedings of the FREENIX Track: 2003 USENIX Annual Technical Conference
+.%P 179-186
+.%D June 9-14, 2003
+.%U http://www.usenix.org/event/usenix03/tech/freenix03/full_papers/dowdeswell/dowdeswell.pdf
+.Re
+.Sh HISTORY
+The
+.Nm
+driver was written by Roland C. Dowdeswell for
+.Nx .
+The
+.Nm
+driver originally appeared in
+.Nx 2.0 .