1DES_CRYPT(3) Linux Programmer's Manual DES_CRYPT(3)
2
6 des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED - fast DES
7 encryption
8
10 #include <rpc/des_crypt.h>
11 int ecb_crypt(char *key, char *data, unsigned int datalen,
13 unsigned int mode);
14 int cbc_crypt(char *key, char *data, unsigned int datalen,
15 unsigned int mode, char *ivec);
16 void des_setparity(char *key);
18 int DES_FAILED(int status);
20
22 ecb_crypt() and cbc_crypt() implement the NBS DES (Data Encryption
23 Standard). These routines are faster and more general purpose than
24 crypt(3). They also are able to utilize DES hardware if it is avail‐
25 able. ecb_crypt() encrypts in ECB (Electronic Code Book) mode, which
26 encrypts blocks of data independently. cbc_crypt() encrypts in CBC
27 (Cipher Block Chaining) mode, which chains together successive blocks.
28 CBC mode protects against insertions, deletions, and substitutions of
29 blocks. Also, regularities in the clear text will not appear in the
30 cipher text.
31 Here is how to use these routines. The first argument, key, is the
33 8-byte encryption key with parity. To set the key's parity, which for
34 DES is in the low bit of each byte, use des_setparity(). The second
35 argument, data, contains the data to be encrypted or decrypted. The
36 third argument, datalen, is the length in bytes of data, which must be
37 a multiple of 8. The fourth argument, mode, is formed by ORing to‐
38 gether some things. For the encryption direction OR in either DES_EN‐
39 CRYPT or DES_DECRYPT. For software versus hardware encryption, OR in
40 either DES_HW or DES_SW. If DES_HW is specified, and there is no hard‐
41 ware, then the encryption is performed in software and the routine re‐
42 turns DESERR_NOHWDEVICE. For cbc_crypt(), the argument ivec is the
43 8-byte initialization vector for the chaining. It is updated to the
44 next initialization vector upon return.
45
47 DESERR_NONE
48 No error.
49 DESERR_NOHWDEVICE
51 Encryption succeeded, but done in software instead of the re‐
52 quested hardware.
53 DESERR_HWERROR
55 An error occurred in the hardware or driver.
56 DESERR_BADPARAM
58 Bad argument to routine.
59 Given a result status stat, the macro DES_FAILED(stat) is false only
61 for the first two statuses.
62
64 These functions were added to glibc in version 2.1.
65 Because they employ the DES block cipher, which is no longer considered
67 secure, ecb_crypt(), ecb_crypt(), crypt_r(), and des_setparity() were
68 removed in glibc 2.28. Applications should switch to a modern cryptog‐
69 raphy library, such as libgcrypt.
70
72 For an explanation of the terms used in this section, see at‐
73 tributes(7).
74 ┌────────────────────────────────────────────┬───────────────┬─────────┐
76 │Interface │ Attribute │ Value │
77 ├────────────────────────────────────────────┼───────────────┼─────────┤
78 │ecb_crypt(), cbc_crypt(), des_setparity() │ Thread safety │ MT-Safe │
79 └────────────────────────────────────────────┴───────────────┴─────────┘
80
82 4.3BSD. Not in POSIX.1.
83
85 des(1), crypt(3), xcrypt(3)
86
88 This page is part of release 5.12 of the Linux man-pages project. A
89 description of the project, information about reporting bugs, and the
90 latest version of this page, can be found at
91 https://www.kernel.org/doc/man-pages/.
92 2021-03-22 DES_CRYPT(3)