.Dd August 11, 1996
.Dt LIBIDEA 3
.Os NetBSD 1.2BETA
.Sh NAME
.Nm idea_setkey_e ,
.Nm idea_setkey_d ,
.Nm idea_keycvt_e_to_d ,
.Nm idea_keycvt_d_to_e ,
.Nm idea_crypt
.Nd IDEA encryption/decryption routines
.Sh SYNOPSIS
.Fd #include <idea.h>
.br
.Nm cc
.Op Ar arguments
.Fl lidea
.br
.Ft void
.Fn idea_setkey_e "const void *key" "IDEA_KEY *ks"
.Ft void
.Fn idea_setkey_d "const void *key" "IDEA_KEY *ks"
.Ft void
.Fn idea_keycvt_e_to_d "const IDEA_KEY *kin" "IDEA_KEY *kout"
.Ft void
.Fn idea_keycvt_d_to_e "const IDEA_KEY *kin" "IDEA_KEY *kout"
.Ft void
.Fn idea_crypt "const void *bufin" "IDEA_KEY *key" "void *bufout"
.Sh DESCRIPTION
These functions perform IDEA encryption and decryption.
.Pp
.Fn idea_setkey_e
and
.Fn idea_setkey_d
take a buffer containing a key, which for IDEA is 128 arbitrary bits (stored
as 16 bytes), and converts it to an
.Dv IDEA_KEY ,
which is an opaque structure used to hold a key in the pre-massaged form used
by
.Fn idea_crypt .
.Pp
.Fn idea_setkey_d_to_e
and
.Fn idea_setkey_e_to_d
take an
.Dv IDEA_KEY
set up for decryption and convert it to one set up for encryption with the
same key, or the other way around, as indicated by their names.  It is
permissible for the two arguments to point to the same
.Dv IDEA_KEY .
.Pp
.Fn idea_crypt
performs the actual encryption or decryption operation, according as whether
the
.Dv IDEA_KEY
passed in is set up for encryption or decryption.
.Fa bufin
is the 64-bit input block, stored as 8 bytes,
.Fa key
is of course the
.Dv IDEA_KEY ,
and
.Fa bufout
is an 8-byte buffer to hold the output block.  It is permissible for
.Fa bufin
and
.Fa bufout
to point to the same buffer.
.Sh ERRORS
These routines
.Dq cannot fail ;
the only failure modes possible for them are due to passing invalid pointers
as arguments.  Such incorrect calls will not be detected by the library; their
effects can range from silent corruption of memory to core dumps.
.Sh BUGS
Code blindly assumes 8-bit
.Do
char
.Dc Ns s.
.Sh AUTHOR
der Mouse,
.Aq mouse@rodents.montreal.qc.ca .