encrypt(3) - Linux manual page (original) (raw)
encrypt(3) Library Functions Manual encrypt(3)
NAME top
encrypt, setkey, encrypt_r, setkey_r - encrypt 64-bit messagesLIBRARY top
Password hashing library (_libcrypt_, _-lcrypt_)SYNOPSIS top
**#define _XOPEN_SOURCE** /* See feature_test_macros(7) */
**#include <unistd.h>**
**[[deprecated]] void encrypt(char** _block_**[64], int** _edflag_**);**
**#define _XOPEN_SOURCE** /* See feature_test_macros(7) */
**#include <stdlib.h>**
**[[deprecated]] void setkey(const char ***_key_**);**
**#define _GNU_SOURCE** /* See feature_test_macros(7) */
**#include <crypt.h>**
**[[deprecated]] void setkey_r(const char ***_key_**, struct crypt_data ***_data_**);**
**[[deprecated]] void encrypt_r(char ***_block_**, int** _edflag_**,**
**struct crypt_data ***_data_**);**DESCRIPTION top
These functions encrypt and decrypt 64-bit messages. The
**setkey**() function sets the key used by **encrypt**(). The _key_
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.
The **encrypt**() function modifies the passed buffer, encoding if
_edflag_ is 0, and decoding if 1 is being passed. Like the _key_
argument, also _block_ is a bit vector representation of the actual
value that is encoded. The result is returned in that same
vector.
These two functions are not reentrant, that is, the key data is
kept in static storage. The functions **setkey_r**() and **encrypt_r**()
are the reentrant versions. They use the following structure to
hold the key data:
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 current_saltbits;
int direction;
int initialized;
};
Before calling **setkey_r**() set _data->initialized_ to zero.RETURN VALUE top
These functions do not return any value.ERRORS top
Set _[errno](../man3/errno.3.html)_ to zero before calling the above functions. On
success, _[errno](../man3/errno.3.html)_ is unchanged.
**ENOSYS** The function is not provided. (For example because of
former USA export restrictions.)ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌────────────────────────┬───────────────┬──────────────────────┐
│ **Interface** │ **Attribute** │ **Value** │
├────────────────────────┼───────────────┼──────────────────────┤
│ **encrypt**(), **setkey**() │ Thread safety │ MT-Unsafe race:crypt │
├────────────────────────┼───────────────┼──────────────────────┤
│ **encrypt_r**(), │ Thread safety │ MT-Safe │
│ **setkey_r**() │ │ │
└────────────────────────┴───────────────┴──────────────────────┘STANDARDS top
**encrypt**()
**setkey**()
POSIX.1-2008.
**encrypt_r**()
**setkey_r**()
None.HISTORY top
Removed in glibc 2.28.
Because they employ the DES block cipher, which is no longer
considered secure, these functions were removed from glibc.
Applications should switch to a modern cryptography library, such
as **libgcrypt**.
**encrypt**()
**setkey**()
POSIX.1-2001, SUS, SVr4.Availability in glibc See crypt(3).
Features in glibc In glibc 2.2, these functions use the DES algorithm.
EXAMPLES top
#define _XOPEN_SOURCE
#include <crypt.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int
main(void)
{
char key[64];
char orig[9] = "eggplant";
char buf[64];
char txt[9];
for (size_t i = 0; i < 64; i++) {
key[i] = rand() & 1;
}
for (size_t i = 0; i < 8; i++) {
for (size_t j = 0; j < 8; j++) {
buf[i * 8 + j] = orig[i] >> j & 1;
}
setkey(key);
}
printf("Before encrypting: %s\n", orig);
encrypt(buf, 0);
for (size_t i = 0; i < 8; i++) {
for (size_t j = 0, txt[i] = '\0'; j < 8; j++) {
txt[i] |= buf[i * 8 + j] << j;
}
txt[8] = '\0';
}
printf("After encrypting: %s\n", txt);
encrypt(buf, 1);
for (size_t i = 0; i < 8; i++) {
for (size_t j = 0, txt[i] = '\0'; j < 8; j++) {
txt[i] |= buf[i * 8 + j] << j;
}
txt[8] = '\0';
}
printf("After decrypting: %s\n", txt);
exit(EXIT_SUCCESS);
}SEE ALSO top
[cbc_crypt(3)](../man3/cbc%5Fcrypt.3.html), [crypt(3)](../man3/crypt.3.html), [ecb_crypt(3)](../man3/ecb%5Fcrypt.3.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.9.1 2024-06-15 encrypt(3)
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