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.\" $Id: krb5_keyblock.3 17385 2006-05-01 08:48:55Z lha $
.\"
.Dd May  1, 2006
.Dt KRB5_KEYBLOCK 3
.Os HEIMDAL
.Sh NAME
.Nm krb5_keyblock ,
.Nm krb5_keyblock_get_enctype ,
.Nm krb5_copy_keyblock ,
.Nm krb5_copy_keyblock_contents ,
.Nm krb5_free_keyblock ,
.Nm krb5_free_keyblock_contents ,
.Nm krb5_generate_random_keyblock ,
.Nm krb5_generate_subkey ,
.Nm krb5_generate_subkey_extended ,
.Nm krb5_keyblock_init ,
.Nm krb5_keyblock_zero ,
.Nm krb5_random_to_key
.Nd Kerberos 5 key handling functions
.Sh LIBRARY
Kerberos 5 Library (libkrb5, -lkrb5)
.Sh SYNOPSIS
.In krb5.h
.Pp
.Li krb5_keyblock ;
.Ft krb5_enctype
.Fo krb5_keyblock_get_enctype
.Fa "const krb5_keyblock *block"
.Fc
.Ft krb5_error_code
.Fo krb5_copy_keyblock
.Fa "krb5_context context"
.Fa "krb5_keyblock **to"
.Fc
.Ft krb5_error_code
.Fo krb5_copy_keyblock_contents
.Fa "krb5_context context"
.Fa "const krb5_keyblock *inblock"
.Fa "krb5_keyblock *to"
.Fc
.Ft void
.Fo krb5_free_keyblock
.Fa "krb5_context context"
.Fa "krb5_keyblock *keyblock"
.Fc
.Ft void
.Fo krb5_free_keyblock_contents
.Fa "krb5_context context"
.Fa "krb5_keyblock *keyblock"
.Fc
.Ft krb5_error_code
.Fo krb5_generate_random_keyblock
.Fa "krb5_context context"
.Fa "krb5_enctype type"
.Fa "krb5_keyblock *key"
.Fc
.Ft krb5_error_code
.Fo krb5_generate_subkey
.Fa "krb5_context context"
.Fa "const krb5_keyblock *key"
.Fa "krb5_keyblock **subkey"
.Fc
.Ft krb5_error_code
.Fo krb5_generate_subkey_extended
.Fa "krb5_context context"
.Fa "const krb5_keyblock *key"
.Fa "krb5_enctype enctype"
.Fa "krb5_keyblock **subkey"
.Fc
.Ft krb5_error_code
.Fo krb5_keyblock_init
.Fa "krb5_context context"
.Fa "krb5_enctype type"
.Fa "const void *data"
.Fa "size_t size"
.Fa "krb5_keyblock *key"
.Fc
.Ft void
.Fo krb5_keyblock_zero
.Fa "krb5_keyblock *keyblock"
.Fc
.Ft krb5_error_code
.Fo krb5_random_to_key
.Fa "krb5_context context"
.Fa "krb5_enctype type"
.Fa "const void *data"
.Fa "size_t size"
.Fa "krb5_keyblock *key"
.Fc
.Sh DESCRIPTION
.Li krb5_keyblock
holds the encryption key for a specific encryption type.
There is no component inside
.Li krb5_keyblock
that is directly referable.
.Pp
.Fn krb5_keyblock_get_enctype
returns the encryption type of the keyblock.
.Pp
.Fn krb5_copy_keyblock
makes a copy the keyblock
.Fa inblock
to the
output
.Fa out .
.Fa out
should be freed by the caller with
.Fa krb5_free_keyblock .
.Pp
.Fn krb5_copy_keyblock_contents
copies the contents of
.Fa inblock
to the
.Fa to
keyblock.
The destination keyblock is overritten.
.Pp
.Fn krb5_free_keyblock
zeros out and frees the content and the keyblock itself.
.Pp
.Fn krb5_free_keyblock_contents
zeros out and frees the content of the keyblock.
.Pp
.Fn krb5_generate_random_keyblock
creates a new content of the keyblock
.Fa key
of type encrytion type
.Fa type .
The content of
.Fa key
is overwritten and not freed, so the caller should be sure it is
freed before calling the function.
.Pp
.Fn krb5_generate_subkey
generates a
.Fa subkey
of the same type as
.Fa key .
The caller must free the subkey with
.Fa krb5_free_keyblock .
.Pp
.Fn krb5_generate_subkey_extended
generates a
.Fa subkey
of the specified encryption type
.Fa type .
If
.Fa type
is
.Dv ETYPE_NULL ,
of the same type as
.Fa key .
The caller must free the subkey with
.Fa krb5_free_keyblock .
.Pp
.Fn krb5_keyblock_init
Fill in
.Fa key
with key data of type
.Fa enctype
from 
.Fa data
of length
.Fa size .
Key should be freed using
.Fn krb5_free_keyblock_contents .
.Pp
.Fn krb5_keyblock_zero
zeros out the keyblock to to make sure no keymaterial is in
memory.
Note that
.Fn krb5_free_keyblock_contents
also zeros out the memory.
.Pp
.Fn krb5_random_to_key
converts the random bytestring to a protocol key according to Kerberos
crypto frame work.
It the resulting key will be of type
.Fa enctype .
It may be assumed that all the bits of the input string are equally
random, even though the entropy present in the random source may be
limited
.\" .Sh EXAMPLES
.Sh SEE ALSO
.Xr krb5_crypto_init 3 ,
.Xr krb5 3 ,
.Xr krb5.conf 5