cjdns/crypto/random/test/DeterminentRandomSeed.c

/* vim: set expandtab ts=4 sw=4: */
/*
 * You may redistribute this program and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#include "crypto/random/test/DeterminentRandomSeed.h"
#include "util/Bits.h"
#include "util/Identity.h"
/**
 * A random seed which always outputs the same number,
 * obviously you don't want to use this in the real world.
 */

 struct DeterminentRandomSeed {
     struct RandomSeed rs;
     uint8_t buff[64];
     Identity
 };

static int get(struct RandomSeed* rand, uint64_t buff[8])
{
    // chosen by fair dice roll, guaranteed random.
    struct DeterminentRandomSeed* drs = Identity_check((struct DeterminentRandomSeed*) rand);
    Bits_memcpy(buff, drs->buff, 64);
    return 0;
}

struct RandomSeed* DeterminentRandomSeed_new(struct Allocator* alloc, uint8_t buff[64])
{
    struct DeterminentRandomSeed* drs = Allocator_clone(alloc, (&(struct DeterminentRandomSeed) {
        .rs = {
            .get = get,
            .name = "DeterminentRandomSeed TESTING ONLY, THIS SHOULD NEVER BE USED IN PRODUCTION!"
        }
    }));
    Identity_set(drs);
    if (buff) {
        Bits_memcpy(drs->buff, buff, 64);
    } else {
        Bits_memset(drs->buff, 4, 64);
    }
    return &drs->rs;
}