5 /* nettle, low-level cryptographics library
7 * Copyright (C) 2001, 2012 Niels Möller
9 * The nettle library is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License as published by
11 * the Free Software Foundation; either version 2.1 of the License, or (at your
12 * option) any later version.
14 * The nettle library is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17 * License for more details.
19 * You should have received a copy of the GNU Lesser General Public License
20 * along with the nettle library; see the file COPYING.LIB. If not, write to
21 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
34 #include "nettle-internal.h"
37 pkcs1_decrypt (unsigned key_size,
39 unsigned *length, uint8_t *message)
41 TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_SIZE);
44 unsigned message_length;
46 TMP_ALLOC(em, key_size);
47 nettle_mpz_get_str_256(key_size, em, m);
50 if (em[0] || em[1] != 2)
53 terminator = memchr(em + 2, 0, key_size - 2);
58 padding = terminator - (em + 2);
62 message_length = key_size - 3 - padding;
64 if (*length < message_length)
67 memcpy(message, terminator + 1, message_length);
68 *length = message_length;