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 datalen,
13 unsigned mode);
14 int cbc_crypt(char *key, char *data, unsigned datalen,
16 unsigned mode, char *ivec);
17 void des_setparity(char *key);
19 int DES_FAILED(int status);
21
23 ecb_crypt() and cbc_crypt() implement the NBS DES (Data Encryption
24 Standard). These routines are faster and more general purpose than
25 crypt(3). They also are able to utilize DES hardware if it is avail‐
26 able. ecb_crypt() encrypts in ECB (Electronic Code Book) mode, which
27 encrypts blocks of data independently. cbc_crypt() encrypts in CBC
28 (Cipher Block Chaining) mode, which chains together successive blocks.
29 CBC mode protects against insertions, deletions and substitutions of
30 blocks. Also, regularities in the clear text will not appear in the
31 cipher text.
32 Here is how to use these routines. The first argument, key, is the
34 8-byte encryption key with parity. To set the key's parity, which for
35 DES is in the low bit of each byte, use des_setparity(). The second
36 argument, data, contains the data to be encrypted or decrypted. The
37 third argument, datalen, is the length in bytes of data, which must be
38 a multiple of 8. The fourth argument, mode, is formed by OR 'ing
39 together some things. For the encryption direction OR in either
40 DES_ENCRYPT or DES_DECRYPT. For software versus hardware encryption,
41 OR in either DES_HW or DES_SW. If DES_HW is specified, and there is no
42 hardware, then the encryption is performed in software and the routine
43 returns DESERR_NOHWDEVICE. For cbc_crypt(), the argument ivec is the
44 8-byte initialization vector for the chaining. It is updated to the
45 next initialization vector upon return.
46
48 DESERR_NONE No error.
49 DESERR_NOHWDEVICE Encryption succeeded, but done in software instead
50 of the requested hardware.
51 DESERR_HWERROR An error occurred in the hardware or driver.
52 DESERR_BADPARAM Bad argument to routine.
53 Given a result status stat, the macro DES_FAILED(stat) is false only
55 for the first two statuses.
56
58 These routines are present in libc 4.6.27 and later, and in glibc 2.1
59 and later.
60
62 4.3BSD. Not in POSIX.1-2001.
63
65 des(1), crypt(3), xcrypt(3)
66
68 This page is part of release 3.22 of the Linux man-pages project. A
69 description of the project, and information about reporting bugs, can
70 be found at http://www.kernel.org/doc/man-pages/.
71 2007-05-18 DES_CRYPT(3)