.\" Copyright (c) 1989, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
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.\"    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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" 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
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.\"
.\"	@(#)caesar.6	8.2 (Berkeley) 11/16/93
.\" %FreeBSD: src/games/caesar/caesar.6,v 1.5.2.2 2001/03/05 18:10:21 ru Exp %
.\" $FreeBSD: doc/ja_JP.eucJP/man/man6/caesar.6,v 1.5 2001/05/14 01:09:38 horikawa Exp $
.\" 以下は参考にした Linux LM のクレジット
.\"
.\" Japanese Version Copyright (c) 1997,1998 MAEHARA Kohichi
.\"         all rights reserved.
.\" Translated Tue Feb 10 00:00:00 JST 1998
.\"         by MAEHARA Kohichi <maeharak@kw.netlaputa.ne.jp>
.\"
.Dd November 16, 1993
.Dt CAESAR 6
.Os
.Sh 名称
.Nm caesar
.Nd シーザー式暗号法の解読
.Sh 書式
.Nm caesar
.Op Ar rotation
.Sh 解説
.Nm
は英文字の出現頻度に関する統計を用いてシーザー式暗号法の解読を行なう
ユーティリティです。
.Nm
は標準入力から読み込み、標準出力へ書き出します。
.Pp
オプション引数に数字で
.Ar rotation
を与えることにより、特定の回転値を指定できます。
.Pp
英文字の出現頻度は以下の通り(多いほうから少ないほうへ)。
.Pp
.Bd -ragged -offset indent
ETAONRISHDLFCMUGPYWBVKXJQZ
.Ed
.Pp
これらの出現頻度をパーセントで示します:
.Pp
.Bd -ragged -offset indent
E(13), T(10.5), A(8.1), O(7.9), N(7.1), R(6.8), I(6.3), S(6.1), H(5.2),
D(3.8), L(3.4), F(2.9), C(2.7), M(2.5), U(2.4), G(2),
P(1.9), Y(1.9),
W(1.5), B(1.4), V(.9), K(.4), X(.15), J(.13), Q(.11), Z(.07).
.Ed
.Pp
.Tn USENET
への暗号化された投稿や、
.Xr fortune 6
プログラムが用いるデータベースのいくつかは、13 文字分回転されています。