des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED - fast DES encryption
int ecb_crypt(char *key, char *data, unsigned datalen,
int cbc_crypt(char *key, char *data, unsigned datalen,
unsigned mode, char *ivec);
void des_setparity(char *key);
int DES_FAILED(int status);
() and cbc_crypt
() implement the NBS DES (Data Encryption
Standard). These routines are faster and more general purpose than
(3). They also are able to utilize DES hardware if it is
() 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,
, contains the data to be encrypted or decrypted. The third
, 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
. For software versus hardware encryption, OR in either
. If DES_HW
is specified, and there is no
hardware, then the encryption is performed in software and the routine returns
. For cbc_crypt
(), the argument ivec
the 8-byte initialization vector for the chaining. It is updated to the next
initialization vector upon return.
- No error.
- Encryption succeeded, but done in software instead of the requested
- An error occurred in the hardware or driver.
- Bad argument to routine.
Given a result status stat
, the macro
is false only for the first two
These functions are present in glibc 2.1 and later.
Because they employ the DES block cipher, which is no longer considered secure,
() were removed in glibc 2.28. Applications should switch
to a modern cryptography library, such as libgcrypt
For an explanation of the terms used in this section, see attributes
|ecb_crypt (), cbc_crypt (), des_setparity ()
4.3BSD. Not in POSIX.1.