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/* nettle, low-level cryptographics library
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* Copyright (C) 2013 Niels Möller
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* The nettle library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or (at your
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* option) any later version.
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* The nettle library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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* License for more details.
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* You should have received a copy of the GNU Lesser General Public License
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* along with the nettle library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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umac_kdf (struct aes_ctx *aes, unsigned index, unsigned length, uint8_t *dst)
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uint8_t block[AES_BLOCK_SIZE];
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WRITE_UINT64 (block, (uint64_t) index);
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for (count = 1; length >= AES_BLOCK_SIZE;
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length -= AES_BLOCK_SIZE, dst += AES_BLOCK_SIZE, count++)
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WRITE_UINT64 (block + 8, count);
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aes_encrypt (aes, AES_BLOCK_SIZE, dst, block);
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WRITE_UINT64 (block + 8, count);
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aes_encrypt (aes, AES_BLOCK_SIZE, block, block);
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memcpy (dst, block, length);
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#define BE_SWAP32(x) x
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#define BE_SWAP32_N(n, x)
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#define BE_SWAP32(x) \
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((ROTL32(8, x) & 0x00FF00FFUL) | \
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(ROTL32(24, x) & 0xFF00FF00UL))
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#define BE_SWAP32_N(n, x) do { \
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for (be_i = 0; be_i < n; be_i++) \
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uint32_t be_x = (x)[be_i]; \
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(x)[be_i] = BE_SWAP32 (be_x); \
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_umac_set_key (uint32_t *l1_key, uint32_t *l2_key,
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uint64_t *l3_key1, uint32_t *l3_key2,
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struct aes_ctx *aes, const uint8_t *key, unsigned n)
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uint8_t buffer[UMAC_KEY_SIZE];
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aes_set_encrypt_key (aes, UMAC_KEY_SIZE, key);
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size = UMAC_DATA_SIZE / 4 + 4*(n-1);
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umac_kdf (aes, 1, size * sizeof(uint32_t), (uint8_t *) l1_key);
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BE_SWAP32_N (size, l1_key);
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umac_kdf (aes, 2, size * sizeof(uint32_t), (uint8_t *) l2_key);
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_umac_l2_init (size, l2_key);
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umac_kdf (aes, 3, size * sizeof(uint64_t), (uint8_t *) l3_key1);
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_umac_l3_init (size, l3_key1);
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/* No need to byteswap these subkeys. */
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umac_kdf (aes, 4, n * sizeof(uint32_t), (uint8_t *) l3_key2);
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umac_kdf (aes, 0, UMAC_KEY_SIZE, buffer);
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aes_set_encrypt_key (aes, UMAC_KEY_SIZE, buffer);