/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */

/* lib/crypto/krb/prf.c */

/*

 * Copyright (C) 2004 by the Massachusetts Institute of Technology.

 * All rights reserved.

 *

 * Export of this software from the United States of America may

 *   require a specific license from the United States Government.

 *   It is the responsibility of any person or organization contemplating

 *   export to obtain such a license before exporting.

 *

 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and

 * distribute this software and its documentation for any purpose and

 * without fee is hereby granted, provided that the above copyright

 * notice appear in all copies and that both that copyright notice and

 * this permission notice appear in supporting documentation, and that

 * the name of M.I.T. not be used in advertising or publicity pertaining

 * to distribution of the software without specific, written prior

 * permission.  Furthermore if you modify this software you must label

 * your software as modified software and not distribute it in such a

 * fashion that it might be confused with the original M.I.T. software.

 * M.I.T. makes no representations about the suitability of

 * this software for any purpose.  It is provided "as is" without express

 * or implied warranty.

 */

/*

 * This contains the implementation of krb5_c_prf, which will find the

 * enctype-specific PRF and then generate pseudo-random data.  This function

 * yields krb5_c_prf_length bytes of output.

 */

#include "crypto_int.h"

krb5_error_code KRB5_CALLCONV

krb5_c_prf_length(krb5_context context, krb5_enctype enctype, size_t *len)

{

    const struct krb5_keytypes *ktp;

    assert(len);

    ktp = find_enctype(enctype);

    if (ktp == NULL)

        return KRB5_BAD_ENCTYPE;

    *len = ktp->prf_length;

    return 0;

}

krb5_error_code KRB5_CALLCONV

krb5_k_prf(krb5_context context, krb5_key key,

           krb5_data *input, krb5_data *output)

{

    const struct krb5_keytypes *ktp;

    krb5_error_code ret;

    assert(input && output);

    assert(output->data);

    ktp = find_enctype(key->keyblock.enctype);

    if (ktp == NULL)

        return KRB5_BAD_ENCTYPE;

    if (ktp->prf == NULL)

        return KRB5_CRYPTO_INTERNAL;

    output->magic = KV5M_DATA;

    if (ktp->prf_length != output->length)

        return KRB5_CRYPTO_INTERNAL;

    ret = ktp->prf(ktp, key, input, output);

    return ret;

}

krb5_error_code KRB5_CALLCONV

krb5_c_prf(krb5_context context, const krb5_keyblock *keyblock,

           krb5_data *input, krb5_data *output)

{

    krb5_key key;

    krb5_error_code ret;

    ret = krb5_k_create_key(context, keyblock, &key);

    if (ret != 0)

        return ret;

    ret = krb5_k_prf(context, key, input, output);

    krb5_k_free_key(context, key);

    return ret;

}