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.\" @(#)des_crypt.3     2.1 88/08/11 4.0 RPCSRC; from 1.16 88/03/02 SMI;

.\" $FreeBSD: src/lib/libc/rpc/des_crypt.3,v 1.4 2000/03/02 09:13:45 sheldonh Exp $

.\"

.TH DES_CRYPT 3  "6 October 1987"

.SH NAME

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

.SH SYNOPSIS

.nf

.B #include 

.LP

.B int ecb_crypt(key, data, datalen, mode)

.B char *key;

.B char *data;

.B unsigned datalen;

.B unsigned mode;

.LP

.B int cbc_crypt(key, data, datalen, mode, ivec)

.B char *key;

.B char *data;

.B unsigned datalen;

.B unsigned mode;

.B char *ivec;

.LP

.B void des_setparity(key)

.B char *key;

.fi

.SH DESCRIPTION

.IX encryption cbc_crypt "" \fLcbc_crypt\fP

.IX "des encryption" cbc_crypt "DES encryption" \fLcbc_crypt\fP

.IX encryption des_setparity "" \fLdes_setparity\fP

.IX "des encryption" des_setparity "DES encryption" \fLdes_setparity\fP

.B ecb_crypt(\|)

and

.B cbc_crypt(\|)

implement the

.SM NBS

.SM DES

(Data Encryption Standard).

These routines are faster and more general purpose than

.BR crypt (3).

They also are able to utilize

.SM DES

hardware if it is available.

.B ecb_crypt(\|)

encrypts in

.SM ECB

(Electronic Code Book)

mode, which encrypts blocks of data independently.

.B cbc_crypt(\|)

encrypts in

.SM CBC

(Cipher Block Chaining)

mode, which chains together

successive blocks.

.SM CBC

mode protects against insertions, deletions and

substitutions of blocks.

Also, regularities in the clear text will

not appear in the cipher text.

.LP

Here is how to use these routines.  The first parameter,

.IR key ,

is the 8-byte encryption key with parity.

To set the key's parity, which for

.SM DES

is in the low bit of each byte, use

.IR des_setparity .

The second parameter,

.IR data ,

contains the data to be encrypted or decrypted.

The

third parameter,

.IR datalen ,

is the length in bytes of

.IR data ,

which must be a multiple of 8. The fourth parameter,

.IR mode ,

is formed by

.SM OR\s0'ing

together some things.  For the encryption direction 'or' in either

.SM DES_ENCRYPT

or

.SM DES_DECRYPT\s0.

For software versus hardware

encryption, 'or' in either

.SM DES_HW

or

.SM DES_SW\s0.

If

.SM DES_HW

is specified, and there is no hardware, then the encryption is performed

in software and the routine returns

.SM DESERR_NOHWDEVICE\s0.

For

.IR cbc_crypt ,

the parameter

.I ivec

is the the 8-byte initialization

vector for the chaining.  It is updated to the next initialization

vector upon return.

.LP

.SH "SEE ALSO"

.BR des (1),

.BR crypt (3)

.SH DIAGNOSTICS

.PD 0

.TP 20

.SM DESERR_NONE

No error.

.TP

.SM DESERR_NOHWDEVICE

Encryption succeeded, but done in software instead of the requested hardware.

.TP

.SM DESERR_HWERR

An error occurred in the hardware or driver.

.TP

.SM DESERR_BADPARAM

Bad parameter to routine.

.PD

.LP

Given a result status

.IR stat ,

the macro

.SM DES_FAILED\c

.BR ( stat )

is false only for the first two statuses.

.SH RESTRICTIONS

These routines are not available in RPCSRC 4.0.

This information is provided to describe the DES interface expected by

Secure RPC.