Ubuntu Manpage: des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED

NAME

       des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED - fast DES encryption

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <rpc/des_crypt.h>

       [[deprecated]] int ecb_crypt(char *key, char data[.datalen],
                                    unsigned int datalen, unsigned int mode);
       [[deprecated]] int cbc_crypt(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);

DESCRIPTION

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.

RETURN VALUE

       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.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                                     │ Attribute     │ Value   │
       ├──────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ecb_crypt(), cbc_crypt(), des_setparity()                                     │ Thread safety │ MT-Safe │
       └──────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       None.

HISTORY

       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.