{"id":6928,"date":"2022-12-20T19:34:22","date_gmt":"2022-12-20T22:34:22","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/encrypt-man3\/"},"modified":"2022-12-20T19:34:22","modified_gmt":"2022-12-20T22:34:22","slug":"encrypt-man3","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/encrypt-man3\/","title":{"rendered":"ENCRYPT (man3)"},"content":{"rendered":"

ENCRYPT<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
RETURN VALUE<\/a>
ERRORS<\/a>
VERSIONS<\/a>
ATTRIBUTES<\/a>
CONFORMING TO<\/a>
NOTES<\/a>
EXAMPLES<\/a>
SEE ALSO<\/a>
COLOPHON<\/a> <\/p>\n

\n

NAME <\/a> <\/h2>\n

encrypt, setkey, encrypt_r, setkey_r \u2212 encrypt 64-bit messages<\/p>\n

SYNOPSIS <\/a> <\/h2>\n

#define _XOPEN_SOURCE<\/b> \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var See feature_test_macros(7) bodies\/ usr\/
#include <\/b><\/p>\n

void encrypt(char<\/b> block<\/i>[64], int<\/b> edflag<\/i>);<\/b><\/p>\n

#define _XOPEN_SOURCE<\/b> \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var See feature_test_macros(7) bodies\/ usr\/
#include <\/b><\/p>\n

void setkey(const char *<\/b>key<\/i>);<\/b><\/p>\n

#define _GNU_SOURCE<\/b> \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var See feature_test_macros(7) bodies\/ usr\/
#include <\/b><\/p>\n

void setkey_r(const char *<\/b>key<\/i>, struct crypt_data *<\/b>data<\/i>);
void encrypt_r(char *<\/b>block<\/i>, int<\/b> edflag<\/i>, struct crypt_data *<\/b>data<\/i>);<\/b><\/p>\n

Each of these requires linking with \u2212lcrypt<\/i>.<\/p>\n

DESCRIPTION <\/a> <\/h2>\n

These functions encrypt and decrypt 64-bit messages. The setkey<\/b>() function sets the key used by encrypt<\/b>(). The key<\/i> argument 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.<\/p>\n

The encrypt<\/b>() function modifies the passed buffer, encoding if edflag<\/i> is 0, and decoding if 1 is being passed. Like the key<\/i> argument, also block<\/i> is a bit vector representation of the actual value that is encoded. The result is returned in that same vector.<\/p>\n

These two functions are not reentrant, that is, the key data is kept in static storage. The functions setkey_r<\/b>() and encrypt_r<\/b>() are the reentrant versions. They use the following structure to hold the key data:<\/p>\n

struct crypt_data {
char keysched[16 bodies manpages.csv script_extrae_body.sh script.sh usr 8];
char sb0[32768];
char sb1[32768];
char sb2[32768];
char sb3[32768];
char crypt_3_buf[14];
char current_salt[2];
long current_saltbits;
int direction;
int initialized;
};<\/p>\n

Before calling setkey_r<\/b>() set data\u2212>initialized<\/i> to zero.<\/p>\n

RETURN VALUE <\/a> <\/h2>\n

These functions do not return any value.<\/p>\n

ERRORS <\/a> <\/h2>\n

Set errno<\/i> to zero before calling the above functions. On success, it is unchanged.<\/p>\n\n\n
<\/td>\n\n

ENOSYS<\/b><\/p>\n<\/td>\n

<\/td>\n\n

The function is not provided. (For example because of former USA export restrictions.)<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

VERSIONS <\/a> <\/h2>\n

Because they employ the DES block cipher, which is no longer considered secure, crypt<\/b>(), crypt_r<\/b>(), setkey<\/b>(), and setkey_r<\/b>() were removed in glibc 2.28. Applications should switch to a modern cryptography library, such as libgcrypt<\/b>.<\/p>\n

ATTRIBUTES <\/a> <\/h2>\n

For an explanation of the terms used in this section, see attributes<\/b>(7).<\/p>\n

\"Image<\/p>\n

CONFORMING TO <\/a> <\/h2>\n

encrypt<\/b>(), setkey<\/b>(): POSIX.1-2001, POSIX.1-2008, SUS, SVr4.<\/p>\n

The functions encrypt_r<\/b>() and setkey_r<\/b>() are GNU extensions.<\/p>\n

NOTES <\/a> <\/h2>\n

Availability in glibc<\/b>
See crypt<\/b>(3).<\/p>\n

Features in glibc<\/b>
In glibc 2.2, these functions use the DES algorithm.<\/p>\n

EXAMPLES <\/a> <\/h2>\n

#define _XOPEN_SOURCE
#include
#include
#include
#include <\/p>\n

int
main(void)
{
char key[64];
char orig[9] = “eggplant”;
char buf[64];
char txt[9];<\/p>\n

for (int i = 0; i < 64; i++) {
key[i] = rand() & 1;
}<\/p>\n

for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
buf[i bodies manpages.csv script_extrae_body.sh script.sh usr 8 + j] = orig[i] >> j & 1;
}
setkey(key);
}
printf(“Before encrypting: %sn”, orig);<\/p>\n

encrypt(buf, 0);
for (int i = 0; i < 8; i++) {
for (int j = 0, txt[i] = ‘\u0000’; j < 8; j++) {
txt[i] |= buf[i bodies manpages.csv script_extrae_body.sh script.sh usr 8 + j] << j;
}
txt[8] = ‘\u0000’;
}
printf(“After encrypting: %sn”, txt);<\/p>\n

encrypt(buf, 1);
for (int i = 0; i < 8; i++) {
for (int j = 0, txt[i] = ‘\u0000’; j < 8; j++) {
txt[i] |= buf[i bodies manpages.csv script_extrae_body.sh script.sh usr 8 + j] << j;
}
txt[8] = ‘\u0000’;
}
printf(“After decrypting: %sn”, txt);
exit(EXIT_SUCCESS);
}<\/p>\n

SEE ALSO <\/a> <\/h2>\n

cbc_crypt<\/b>(3), crypt<\/b>(3), ecb_crypt<\/b>(3),<\/p>\n

COLOPHON <\/a> <\/h2>\n

This page is part of release 5.10 of the Linux man-pages<\/i> project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https:\/\/www.kernel.org\/doc\/man\u2212pages\/.<\/p>\n

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encrypt, setkey, encrypt_r, setkey_r \u2212 encrypt 64-bit messages <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2536],"tags":[2538,1777,3007],"class_list":["post-6928","post","type-post","status-publish","format-standard","hentry","category-3-llamadas-de-bibliotecas","tag-2538","tag-encrypt","tag-man3"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/6928","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=6928"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/6928\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=6928"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=6928"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=6928"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}