freebsd-skq/lib/libc/rpc/des_crypt.3

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.\" @(#)des_crypt.3 2.1 88/08/11 4.0 RPCSRC; from 1.16 88/03/02 SMI;
1999-08-28 00:22:10 +00:00
.\" $FreeBSD$
.\"
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.Dd October 6, 1987
.Dt DES_CRYPT 3
.Os
.Sh NAME
.Nm des_crypt , ecb_crypt , cbc_crypt , des_setparity
.Nd "fast DES encryption"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd "#include <rpc/des_crypt.h>"
.Ft int
.Fn ecb_crypt "char *key" "char *data" "unsigned datalen" "unsigned mode"
.Ft int
.Fn cbc_crypt "char *key" "char *data" "unsigned datalen" "unsigned mode" "char *ivec"
.Ft void
.Fn des_setparity "char *key"
.Sh DESCRIPTION
.Fn ecb_crypt
and
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.Fn cbc_crypt
implement the
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.Tn NBS
.Tn DES
(Data Encryption Standard).
These routines are faster and more general purpose than
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.Xr crypt 3 .
They also are able to utilize
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.Tn DES
hardware if it is available.
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.Fn ecb_crypt
encrypts in
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.Tn ECB
(Electronic Code Book)
mode, which encrypts blocks of data independently.
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.Fn cbc_crypt
encrypts in
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.Tn CBC
(Cipher Block Chaining)
mode, which chains together
successive blocks.
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.Tn CBC
mode protects against insertions, deletions and
substitutions of blocks.
Also, regularities in the clear text will
not appear in the cipher text.
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.Pp
Here is how to use these routines.
The first parameter,
.Fa key ,
is the 8-byte encryption key with parity.
To set the key's parity, which for
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.Tn DES
is in the low bit of each byte, use
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.Fn des_setparity .
The second parameter,
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.Fa data ,
contains the data to be encrypted or decrypted.
The
third parameter,
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.Fa datalen ,
is the length in bytes of
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.Fa data ,
which must be a multiple of 8.
The fourth parameter,
.Fa mode ,
is formed by
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.Em OR Ns 'ing
together some things.
For the encryption direction
.Em OR
in either
.Dv DES_ENCRYPT
or
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.Dv DES_DECRYPT .
For software versus hardware
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encryption,
.Em OR
in either
.Dv DES_HW
or
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.Dv DES_SW .
If
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.Dv DES_HW
is specified, and there is no hardware, then the encryption is performed
in software and the routine returns
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.Er DESERR_NOHWDEVICE .
For
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.Fn cbc_crypt ,
the parameter
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.Fa ivec
is the the 8-byte initialization
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vector for the chaining.
It is updated to the next initialization
vector upon return.
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.Sh ERRORS
.Bl -tag -width [DESERR_NOHWDEVICE] -compact
.It Bq Er DESERR_NONE
No error.
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.It Bq Er DESERR_NOHWDEVICE
Encryption succeeded, but done in software instead of the requested hardware.
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.It Bq Er DESERR_HWERR
An error occurred in the hardware or driver.
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.It Bq Er DESERR_BADPARAM
Bad parameter to routine.
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.El
.Pp
Given a result status
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.Va stat ,
the macro
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.Fn DES_FAILED stat
is false only for the first two statuses.
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.Sh SEE ALSO
.\" .Xr des 1 ,
.Xr crypt 3
.Sh RESTRICTIONS
These routines are not available in RPCSRC 4.0.
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This information is provided to describe the
.Tn DES
interface expected by
Secure RPC.