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

/*

 * COPYRIGHT (c) 2006

 * The Regents of the University of Michigan

 * ALL RIGHTS RESERVED

 *

 * Permission is granted to use, copy, create derivative works

 * and redistribute this software and such derivative works

 * for any purpose, so long as the name of The University of

 * Michigan is not used in any advertising or publicity

 * pertaining to the use of distribution of this software

 * without specific, written prior authorization.  If the

 * above copyright notice or any other identification of the

 * University of Michigan is included in any copy of any

 * portion of this software, then the disclaimer below must

 * also be included.

 *

 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION

 * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY

 * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF

 * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING

 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE

 * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE

 * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR

 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING

 * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN

 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGES.

 */

/*

 * Create a key given random data.  It is assumed that random_key has

 * already been initialized and random_key->contents have been allocated

 * with the correct length.

 */

#include "crypto_int.h"

krb5_error_code KRB5_CALLCONV

krb5_c_random_to_key(krb5_context context, krb5_enctype enctype,

                     krb5_data *random_data, krb5_keyblock *random_key)

{

    krb5_error_code ret;

    const struct krb5_keytypes *ktp;

    if (random_data == NULL || random_key == NULL ||

        random_key->contents == NULL)

        return EINVAL;

    ktp = find_enctype(enctype);

    if (ktp == NULL)

        return KRB5_BAD_ENCTYPE;

    if (random_key->length != ktp->enc->keylength)

        return KRB5_BAD_KEYSIZE;

    ret = ktp->rand2key(random_data, random_key);

    if (ret)

        zap(random_key->contents, random_key->length);

    return ret;

}

krb5_error_code

k5_rand2key_direct(const krb5_data *randombits, krb5_keyblock *keyblock)

{

    if (randombits->length != keyblock->length)

        return KRB5_CRYPTO_INTERNAL;

    keyblock->magic = KV5M_KEYBLOCK;

    memcpy(keyblock->contents, randombits->data, randombits->length);

    return 0;

}

static inline void

eighth_byte(unsigned char *b)

{

    b[7] = (((b[0] & 1) << 1) | ((b[1] & 1) << 2) | ((b[2] & 1) << 3) |

            ((b[3] & 1) << 4) | ((b[4] & 1) << 5) | ((b[5] & 1) << 6) |

            ((b[6] & 1) << 7));

}

krb5_error_code

k5_rand2key_des(const krb5_data *randombits, krb5_keyblock *keyblock)

{

    if (randombits->length != 7)

        return(KRB5_CRYPTO_INTERNAL);

    keyblock->magic = KV5M_KEYBLOCK;

    /* Take the seven bytes, move them around into the top 7 bits of the

     * 8 key bytes, then compute the parity bits. */

    memcpy(keyblock->contents, randombits->data, randombits->length);

    eighth_byte(keyblock->contents);

    k5_des_fixup_key_parity(keyblock->contents);

    return 0;

}

krb5_error_code

k5_rand2key_des3(const krb5_data *randombits, krb5_keyblock *keyblock)

{

    int i;

    if (randombits->length != 21)

        return KRB5_CRYPTO_INTERNAL;

    keyblock->magic = KV5M_KEYBLOCK;

    /* Take the seven bytes, move them around into the top 7 bits of the

     * 8 key bytes, then compute the parity bits.  Do this three times. */

    for (i = 0; i < 3; i++) {

        memcpy(&keyblock->contents[i * 8], &randombits->data[i * 7], 7);

        eighth_byte(&keyblock->contents[i * 8]);

        k5_des_fixup_key_parity(&keyblock->contents[i * 8]);

    }

    return 0;

}