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Diffstat (limited to 'man3/encrypt.3')
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diff --git a/man3/encrypt.3 b/man3/encrypt.3 new file mode 100644 index 000000000..a1cad967b --- /dev/null +++ b/man3/encrypt.3 @@ -0,0 +1,140 @@ +.\" Copyright 2000 Nicolás Lichtmaier <nick@debian.org> +.\" Created 2000-07-22 00:52-0300 +.\" +.\" This is free documentation; you can redistribute it and/or +.\" modify it under the terms of the GNU General Public License as +.\" published by the Free Software Foundation; either version 2 of +.\" the License, or (at your option) any later version. +.\" +.\" The GNU General Public License's references to "object code" +.\" and "executables" are to be interpreted as the output of any +.\" document formatting or typesetting system, including +.\" intermediate and printed output. +.\" +.\" This manual is distributed in the hope that it will be useful, +.\" but WITHOUT ANY WARRANTY; without even the implied warranty of +.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +.\" GNU General Public License for more details. +.\" +.\" Modified 2002-07-23 19:21:35 CEST 2002 Walter Harms +.\" <walter.harms@informatik.uni-oldenburg.de> +.\" +.\" Modified 2003-04-04, aeb +.\" +.TH ENCRYPT 3 2003-04-04 "glibc2" "Cryptographic Functions" +.SH NAME +encrypt, setkey, encrypt_r, setkey_r \- encrypt 64-bit messages +.SH SYNOPSIS +.B #define _XOPEN_SOURCE +.br +.B #include <unistd.h> +.sp +.BI "void encrypt(char " block "[64], int " edflag ); +.sp +.B #define _XOPEN_SOURCE +.br +.B #include <stdlib.h> +.sp +.BI "void setkey(const char *" key ); +.sp +.B #define _GNU_SOURCE +.br +.BI "#include <crypt.h>" +.sp +.BI "void setkey_r (const char *" key ", struct crypt_data *" data ); +.br +.BI "void encrypt_r (char *" block ", int " edflag ", struct crypt_data *" data ); +.sp +Each of these requires linking with +.BR -lcrypt . +.SH DESCRIPTION +These functions encrypt and decrypt 64-bit messages. The +.B setkey() +function sets the key used by +.BR encrypt() . +The +.I key +parameter used here is an array of 64 bytes, each of which has +numerical value 1 or 0. The bytes key[n] where n=8*i-1 are ignored, +so that the effective key length is 56 bits. +.PP +The encrypt() function modifies the passed buffer, encoding if +.I edflag +is 0, and decoding if 1 is being passed. Like the key parameter also +.I block +is a bit vector representation of the actual value that is encoded. +The result is returned in that same vector. +.PP +These two functions are not reentrant, that is, the key data is +kept in static storage. The functions +.B setkey_r() +and +.B encrypt_r() +are the reentrant versions. They use the following +structure to hold the key data: +.RS +.nf +struct crypt_data { + char keysched[16 * 8]; + char sb0[32768]; + char sb1[32768]; + char sb2[32768]; + char sb3[32768]; + char crypt_3_buf[14]; + char current_salt[2]; + long int current_saltbits; + int direction, initialized; +}; +.fi +.RE +Before calling +.B setkey_r() +set +.I data->initialized +to zero. +.SH "RETURN VALUE" +These functions do not return any value. +.SH ERRORS +Set +.I errno +to zero before calling the above functions. +On success, it is unchanged. +.TP +.BR ENOSYS +The function is not provided. +(For example because of former USA export restrictions.) +.SH EXAMPLE +You need to link with libcrypt to compile this example with glibc2.2. +To do useful work the key[] and txt[] array must be filled with a +useful bit pattern. Note that the <crypt.h> header unconditionally +gives the prototypes for setkey() and encrypt(). +.sp +.nf +#include <crypt.h> + +main() { + char key[64]; /* bit pattern for key */ + char txt[64]; /* bit pattern for messages */ + setkey(key); + encrypt(txt, 0); /* encode */ + encrypt(txt, 1); /* decode */ +} +.fi +.SH "NOTE" +In glibc2.2 these functions use the DES algorithm. +.SH "CONFORMING TO" +The functions +.B encrypt() +and +.B setkey() +conform to SVID, SUSv2, and POSIX 1003.1-2001. +The functions +.B encrypt_r() +and +.B setkey_r() +are GNU extensions. +.SH "SEE ALSO" +.BR cbc_crypt (3), +.BR crypt (3), +.BR ecb_crypt (3), +.BR fcrypt (3) |