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Unix SMB/CIFS implementation.
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Interface header: HMAC SHA-256 code
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Copyright (C) Andrew Tridgell 2008
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based in hmacsha1.c which is:
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Copyright (C) Stefan Metzmacher
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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taken direct from rfc2202 implementation and modified for suitable use
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#include "../lib/crypto/crypto.h"
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/***********************************************************************
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the rfc 2104/2202 version of hmac_sha256 initialisation.
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***********************************************************************/
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_PUBLIC_ void hmac_sha256_init(const uint8_t *key, size_t key_len, struct HMACSHA256Context *ctx)
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uint8_t tk[SHA256_DIGEST_LENGTH];
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/* if key is longer than 64 bytes reset it to key=HASH(key) */
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SHA256_Update(&tctx, key, key_len);
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SHA256_Final(tk, &tctx);
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key_len = SHA256_DIGEST_LENGTH;
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/* start out by storing key in pads */
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ZERO_STRUCT(ctx->k_ipad);
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ZERO_STRUCT(ctx->k_opad);
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memcpy( ctx->k_ipad, key, key_len);
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memcpy( ctx->k_opad, key, key_len);
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/* XOR key with ipad and opad values */
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ctx->k_ipad[i] ^= 0x36;
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ctx->k_opad[i] ^= 0x5c;
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SHA256_Init(&ctx->ctx);
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SHA256_Update(&ctx->ctx, ctx->k_ipad, 64);
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/***********************************************************************
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update hmac_sha256 "inner" buffer
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***********************************************************************/
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_PUBLIC_ void hmac_sha256_update(const uint8_t *data, size_t data_len, struct HMACSHA256Context *ctx)
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SHA256_Update(&ctx->ctx, data, data_len); /* then text of datagram */
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/***********************************************************************
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finish off hmac_sha256 "inner" buffer and generate outer one.
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***********************************************************************/
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_PUBLIC_ void hmac_sha256_final(uint8_t digest[SHA256_DIGEST_LENGTH], struct HMACSHA256Context *ctx)
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SHA256_Final(digest, &ctx->ctx);
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SHA256_Update(&ctx_o, ctx->k_opad, 64);
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SHA256_Update(&ctx_o, digest, SHA256_DIGEST_LENGTH);
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SHA256_Final(digest, &ctx_o);