diff options
Diffstat (limited to 'port/caesar')
| -rw-r--r-- | port/caesar/.gitignore | 2 | ||||
| -rw-r--r-- | port/caesar/Makefile | 10 | ||||
| -rw-r--r-- | port/caesar/caesar.6 | 73 | ||||
| -rw-r--r-- | port/caesar/caesar.c | 159 | ||||
| -rw-r--r-- | port/caesar/rot13.sh | 33 |
5 files changed, 277 insertions, 0 deletions
diff --git a/port/caesar/.gitignore b/port/caesar/.gitignore new file mode 100644 index 00000000..e2c3034b --- /dev/null +++ b/port/caesar/.gitignore @@ -0,0 +1,2 @@ +caesar +rot13 diff --git a/port/caesar/Makefile b/port/caesar/Makefile new file mode 100644 index 00000000..3910ae5e --- /dev/null +++ b/port/caesar/Makefile @@ -0,0 +1,10 @@ +all: caesar rot13 + +clean: + rm -f caesar rot13 + +install: + mkdir -p ~/.local/bin ~/.local/share/man/man6 + cp caesar rot13 ~/.local/bin + cp caesar.6 ~/.local/share/man/man6 + cp caesar.6 ~/.local/share/man/man6/rot13.6 diff --git a/port/caesar/caesar.6 b/port/caesar/caesar.6 new file mode 100644 index 00000000..4c4bbfb4 --- /dev/null +++ b/port/caesar/caesar.6 @@ -0,0 +1,73 @@ +.\" 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: +.\" 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. +.\" 3. 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 +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS 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. +.\" +.\" @(#)caesar.6 8.2 (Berkeley) 11/16/93 +.\" $FreeBSD: releng/11.2/usr.bin/caesar/caesar.6 216239 2010-12-06 19:12:51Z uqs $ +.\" +.Dd November 16, 1993 +.Dt CAESAR 6 +.Os +.Sh NAME +.Nm caesar , rot13 +.Nd decrypt caesar ciphers +.Sh SYNOPSIS +.Nm +.Op Ar rotation +.Nm rot13 +.Sh DESCRIPTION +The +.Nm +utility attempts to decrypt caesar ciphers using English letter frequency +statistics. +.Nm Caesar +reads from the standard input and writes to the standard output. +.Pp +The optional numerical argument +.Ar rotation +may be used to specify a specific rotation value. +If invoked as +.Nm rot13 , +a rotation value of 13 will be used. +.Pp +The frequency (from most common to least) of English letters is as follows: +.Bd -ragged -offset indent +ETAONRISHDLFCMUGPYWBVKXJQZ +.Ed +.Pp +Their frequencies as a percentage are as follows: +.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 +Rotated postings to +.Tn USENET +and some of the databases used by the +.Xr fortune 6 +program are rotated by 13 characters. diff --git a/port/caesar/caesar.c b/port/caesar/caesar.c new file mode 100644 index 00000000..7f4009fd --- /dev/null +++ b/port/caesar/caesar.c @@ -0,0 +1,159 @@ +/* + * Copyright (c) 1989, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Rick Adams. + * + * Authors: + * Stan King, John Eldridge, based on algorithm suggested by + * Bob Morris + * 29-Sep-82 + * + * 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. + * 3. 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 + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS 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. + */ + +#if 0 +#ifndef lint +static const char copyright[] = +"@(#) Copyright (c) 1989, 1993\n\ + The Regents of the University of California. All rights reserved.\n"; +#endif /* not lint */ + +#ifndef lint +static const char sccsid[] = "@(#)caesar.c 8.1 (Berkeley) 5/31/93"; +#endif /* not lint */ +#endif +#include <sys/cdefs.h> +__FBSDID("$FreeBSD: releng/11.2/usr.bin/caesar/caesar.c 241846 2012-10-22 03:06:53Z eadler $"); + +#include <errno.h> +#include <math.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <ctype.h> +#include <unistd.h> + +#define LINELENGTH 2048 +#define ROTATE(ch, perm) \ + isascii(ch) ? ( \ + isupper(ch) ? ('A' + (ch - 'A' + perm) % 26) : \ + islower(ch) ? ('a' + (ch - 'a' + perm) % 26) : ch) : ch + +/* + * letter frequencies (taken from some unix(tm) documentation) + * (unix is a trademark of Bell Laboratories) + */ +static double stdf[26] = { + 7.97, 1.35, 3.61, 4.78, 12.37, 2.01, 1.46, 4.49, 6.39, 0.04, + 0.42, 3.81, 2.69, 5.92, 6.96, 2.91, 0.08, 6.63, 8.77, 9.68, + 2.62, 0.81, 1.88, 0.23, 2.07, 0.06, +}; + +static void printit(char *); + +int +main(int argc, char **argv) +{ + int ch, dot, i, nread, winnerdot = 0; + char *inbuf; + int obs[26], try, winner; + + if (argc > 1) + printit(argv[1]); + + if (!(inbuf = malloc((size_t)LINELENGTH))) { + (void)fprintf(stderr, "caesar: out of memory.\n"); + exit(1); + } + + /* adjust frequency table to weight low probs REAL low */ + for (i = 0; i < 26; ++i) + stdf[i] = log(stdf[i]) + log(26.0 / 100.0); + + /* zero out observation table */ + bzero(obs, 26 * sizeof(int)); + + if ((nread = read(STDIN_FILENO, inbuf, (size_t)LINELENGTH)) < 0) { + (void)fprintf(stderr, "caesar: %s\n", strerror(errno)); + exit(1); + } + for (i = nread; i--;) { + ch = (unsigned char) inbuf[i]; + if (isascii(ch)) { + if (islower(ch)) + ++obs[ch - 'a']; + else if (isupper(ch)) + ++obs[ch - 'A']; + } + } + + /* + * now "dot" the freqs with the observed letter freqs + * and keep track of best fit + */ + for (try = winner = 0; try < 26; ++try) { /* += 13) { */ + dot = 0; + for (i = 0; i < 26; i++) + dot += obs[i] * stdf[(i + try) % 26]; + /* initialize winning score */ + if (try == 0) + winnerdot = dot; + if (dot > winnerdot) { + /* got a new winner! */ + winner = try; + winnerdot = dot; + } + } + + for (;;) { + for (i = 0; i < nread; ++i) { + ch = (unsigned char) inbuf[i]; + putchar(ROTATE(ch, winner)); + } + if (nread < LINELENGTH) + break; + if ((nread = read(STDIN_FILENO, inbuf, (size_t)LINELENGTH)) < 0) { + (void)fprintf(stderr, "caesar: %s\n", strerror(errno)); + exit(1); + } + } + exit(0); +} + +static void +printit(char *arg) +{ + int ch, rot; + + if ((rot = atoi(arg)) < 0) { + (void)fprintf(stderr, "caesar: bad rotation value.\n"); + exit(1); + } + while ((ch = getchar()) != EOF) + putchar(ROTATE(ch, rot)); + exit(0); +} diff --git a/port/caesar/rot13.sh b/port/caesar/rot13.sh new file mode 100644 index 00000000..19f8aecf --- /dev/null +++ b/port/caesar/rot13.sh @@ -0,0 +1,33 @@ +#!/bin/sh - +# +# Copyright (c) 1992, 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: +# 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. +# 3. 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 +# ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS 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. +# +# @(#)rot13.sh 8.1 (Berkeley) 5/31/93 +# $FreeBSD: releng/11.2/usr.bin/caesar/rot13.sh 278616 2015-02-12 05:35:00Z cperciva $ + +exec /usr/bin/caesar 13 "$@" |