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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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des_crypt(3) Library Functions Manual des_crypt(3)
des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED - fast
DES encryption
Standard C library (libc, -lc)
#include <rpc/des_crypt.h>
[[deprecated]] int ecb_crypt(unsigned int datalen;
char *key, char data[datalen],
unsigned int datalen, unsigned int mode);
[[deprecated]] int cbc_crypt(unsigned int datalen;
char *key, char data[datalen],
unsigned int datalen, unsigned int mode,
char *ivec);
[[deprecated]] void des_setparity(char *key);
[[deprecated]] int DES_FAILED(int status);
ecb_crypt() and cbc_crypt() implement the NBS DES (Data Encryption
Standard). These routines are faster and more general purpose
than crypt(3). They also are able to utilize DES hardware if it
is available. ecb_crypt() encrypts in ECB (Electronic Code Book)
mode, which encrypts blocks of data independently. cbc_crypt()
encrypts in CBC (Cipher Block Chaining) mode, which chains
together successive blocks. CBC mode protects against insertions,
deletions, and substitutions of blocks. Also, regularities in the
clear text will not appear in the cipher text.
Here is how to use these routines. The first argument, key, is
the 8-byte encryption key with parity. To set the key's parity,
which for DES is in the low bit of each byte, use des_setparity().
The second argument, data, contains the data to be encrypted or
decrypted. The third argument, datalen, is the length in bytes of
data, which must be a multiple of 8. The fourth argument, mode,
is formed by ORing together some things. For the encryption
direction OR in either DES_ENCRYPT or DES_DECRYPT. For software
versus hardware encryption, OR in either DES_HW or DES_SW. If
DES_HW is specified, and there is no hardware, then the encryption
is performed in software and the routine returns
DESERR_NOHWDEVICE. For cbc_crypt(), the argument ivec is the
8-byte initialization vector for the chaining. It is updated to
the next initialization vector upon return.
DESERR_NONE
No error.
DESERR_NOHWDEVICE
Encryption succeeded, but done in software instead of the
requested hardware.
DESERR_HWERROR
An error occurred in the hardware or driver.
DESERR_BADPARAM
Bad argument to routine.
Given a result status stat, the macro DES_FAILED(stat) is false
only for the first two statuses.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│ ecb_crypt(), cbc_crypt(), │ Thread safety │ MT-Safe │
│ des_setparity() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘
None.
4.3BSD. glibc 2.1. Removed in glibc 2.28.
Because they employ the DES block cipher, which is no longer
considered secure, these functions were removed. Applications
should switch to a modern cryptography library, such as libgcrypt.
des(1), crypt(3), xcrypt(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-06-28 des_crypt(3)
Pages that refer to this page: encrypt(3), xcrypt(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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