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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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umac128_set_key (struct umac128_ctx *ctx, const uint8_t *key)
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_umac_set_key (ctx->l1_key, ctx->l2_key, ctx->l3_key1, ctx->l3_key2,
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&ctx->pdf_key, key, 4);
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memset (ctx->nonce, 0, sizeof(ctx->nonce));
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ctx->nonce_length = sizeof(ctx->nonce);
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/* Initialize buffer */
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ctx->count = ctx->index = 0;
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umac128_set_nonce (struct umac128_ctx *ctx,
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unsigned nonce_length, const uint8_t *nonce)
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assert (nonce_length > 0);
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assert (nonce_length <= AES_BLOCK_SIZE);
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memcpy (ctx->nonce, nonce, nonce_length);
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memset (ctx->nonce + nonce_length, 0, AES_BLOCK_SIZE - nonce_length);
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ctx->nonce_length = nonce_length;
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#define UMAC128_BLOCK(ctx, block) do { \
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uint64_t __umac128_y[4]; \
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_umac_nh_n (__umac128_y, 4, ctx->l1_key, UMAC_DATA_SIZE, block); \
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__umac128_y[0] += 8*UMAC_DATA_SIZE; \
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__umac128_y[1] += 8*UMAC_DATA_SIZE; \
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__umac128_y[2] += 8*UMAC_DATA_SIZE; \
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__umac128_y[3] += 8*UMAC_DATA_SIZE; \
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_umac_l2 (ctx->l2_key, ctx->l2_state, 4, ctx->count++, __umac128_y); \
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umac128_update (struct umac128_ctx *ctx,
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unsigned length, const uint8_t *data)
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MD_UPDATE (ctx, length, data, UMAC128_BLOCK, (void)0);
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umac128_digest (struct umac128_ctx *ctx,
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unsigned length, uint8_t *digest)
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assert (length <= 16);
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if (ctx->index > 0 || ctx->count == 0)
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/* Zero pad to multiple of 32 */
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unsigned pad = (ctx->index > 0) ? 31 & - ctx->index : 32;
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memset (ctx->block + ctx->index, 0, pad);
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_umac_nh_n (y, 4, ctx->l1_key, ctx->index + pad, ctx->block);
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y[0] += 8 * ctx->index;
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y[1] += 8 * ctx->index;
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y[2] += 8 * ctx->index;
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y[3] += 8 * ctx->index;
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_umac_l2 (ctx->l2_key, ctx->l2_state, 4, ctx->count++, y);
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assert (ctx->count > 0);
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aes_encrypt (&ctx->pdf_key, AES_BLOCK_SIZE,
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(uint8_t *) tag, ctx->nonce);
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INCREMENT (ctx->nonce_length, ctx->nonce);
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_umac_l2_final (ctx->l2_key, ctx->l2_state, 4, ctx->count);
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for (i = 0; i < 4; i++)
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tag[i] ^= ctx->l3_key2[i] ^ _umac_l3 (ctx->l3_key1 + 8*i,
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ctx->l2_state + 2*i);
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memcpy (digest, tag, length);
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ctx->count = ctx->index = 0;