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192 lines
6.9 KiB
192 lines
6.9 KiB
/* ec_dh.c - TinyCrypt implementation of EC-DH */ |
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/* |
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* Copyright (c) 2014, Kenneth MacKay |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions are met: |
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* * Redistributions of source code must retain the above copyright notice, |
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* this list of conditions and the following disclaimer. |
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* * Redistributions in binary form must reproduce the above copyright notice, |
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* this list of conditions and the following disclaimer in the documentation |
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* and/or other materials provided with the distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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/* |
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* Copyright (C) 2017 by Intel Corporation, All Rights Reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions are met: |
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* |
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* - Redistributions of source code must retain the above copyright notice, |
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* this list of conditions and the following disclaimer. |
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* |
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* - Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* |
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* - Neither the name of Intel Corporation nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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#include <tinycrypt/constants.h> |
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#include <tinycrypt/ecc.h> |
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#include <tinycrypt/ecc_dh.h> |
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#include <tinycrypt/utils.h> |
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#include <string.h> |
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int uECC_make_key_with_d(uint8_t *public_key, uint8_t *private_key, |
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unsigned int *d, uECC_Curve curve) |
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{ |
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uECC_word_t _private[NUM_ECC_WORDS]; |
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uECC_word_t _public[NUM_ECC_WORDS * 2]; |
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/* This function is designed for test purposes-only (such as validating NIST |
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* test vectors) as it uses a provided value for d instead of generating |
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* it uniformly at random. */ |
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memcpy (_private, d, NUM_ECC_BYTES); |
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/* Computing public-key from private: */ |
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if (EccPoint_compute_public_key(_public, _private, curve)) { |
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/* Converting buffers to correct bit order: */ |
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uECC_vli_nativeToBytes(private_key, |
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BITS_TO_BYTES(curve->num_n_bits), |
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_private); |
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uECC_vli_nativeToBytes(public_key, |
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curve->num_bytes, |
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_public); |
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uECC_vli_nativeToBytes(public_key + curve->num_bytes, |
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curve->num_bytes, |
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_public + curve->num_words); |
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/* erasing temporary buffer used to store secret: */ |
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_set_secure(_private, 0, NUM_ECC_BYTES); |
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return 1; |
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} |
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return 0; |
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} |
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int uECC_make_key(uint8_t *public_key, uint8_t *private_key, uECC_Curve curve) |
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{ |
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uECC_word_t _random[NUM_ECC_WORDS * 2]; |
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uECC_word_t _private[NUM_ECC_WORDS]; |
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uECC_word_t _public[NUM_ECC_WORDS * 2]; |
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uECC_word_t tries; |
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for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) { |
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/* Generating _private uniformly at random: */ |
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uECC_RNG_Function rng_function = uECC_get_rng(); |
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if (!rng_function || |
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!rng_function((uint8_t *)_random, 2 * NUM_ECC_WORDS*uECC_WORD_SIZE)) { |
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return 0; |
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} |
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/* computing modular reduction of _random (see FIPS 186.4 B.4.1): */ |
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uECC_vli_mmod(_private, _random, curve->n, BITS_TO_WORDS(curve->num_n_bits)); |
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/* Computing public-key from private: */ |
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if (EccPoint_compute_public_key(_public, _private, curve)) { |
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/* Converting buffers to correct bit order: */ |
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uECC_vli_nativeToBytes(private_key, |
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BITS_TO_BYTES(curve->num_n_bits), |
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_private); |
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uECC_vli_nativeToBytes(public_key, |
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curve->num_bytes, |
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_public); |
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uECC_vli_nativeToBytes(public_key + curve->num_bytes, |
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curve->num_bytes, |
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_public + curve->num_words); |
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/* erasing temporary buffer that stored secret: */ |
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_set_secure(_private, 0, NUM_ECC_BYTES); |
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return 1; |
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} |
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} |
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return 0; |
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} |
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int uECC_shared_secret(const uint8_t *public_key, const uint8_t *private_key, |
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uint8_t *secret, uECC_Curve curve) |
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{ |
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uECC_word_t _public[NUM_ECC_WORDS * 2]; |
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uECC_word_t _private[NUM_ECC_WORDS]; |
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uECC_word_t tmp[NUM_ECC_WORDS]; |
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uECC_word_t *p2[2] = {_private, tmp}; |
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uECC_word_t *initial_Z = 0; |
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uECC_word_t carry; |
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wordcount_t num_words = curve->num_words; |
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wordcount_t num_bytes = curve->num_bytes; |
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int r; |
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/* Converting buffers to correct bit order: */ |
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uECC_vli_bytesToNative(_private, |
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private_key, |
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BITS_TO_BYTES(curve->num_n_bits)); |
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uECC_vli_bytesToNative(_public, |
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public_key, |
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num_bytes); |
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uECC_vli_bytesToNative(_public + num_words, |
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public_key + num_bytes, |
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num_bytes); |
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/* Regularize the bitcount for the private key so that attackers cannot use a |
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* side channel attack to learn the number of leading zeros. */ |
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carry = regularize_k(_private, _private, tmp, curve); |
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/* If an RNG function was specified, try to get a random initial Z value to |
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* improve protection against side-channel attacks. */ |
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if (uECC_get_rng()) { |
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if (!uECC_generate_random_int(p2[carry], curve->p, num_words)) { |
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r = 0; |
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goto clear_and_out; |
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} |
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initial_Z = p2[carry]; |
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} |
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EccPoint_mult(_public, _public, p2[!carry], initial_Z, curve->num_n_bits + 1, |
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curve); |
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uECC_vli_nativeToBytes(secret, num_bytes, _public); |
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r = !EccPoint_isZero(_public, curve); |
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clear_and_out: |
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/* erasing temporary buffer used to store secret: */ |
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_set_secure(p2, 0, sizeof(p2)); |
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_set_secure(tmp, 0, sizeof(tmp)); |
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_set_secure(_private, 0, sizeof(_private)); |
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return r; |
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}
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