92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
/* arcfour.h */
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/*
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This file is part of the AVR-Crypto-Lib.
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Copyright (C) 2008 Daniel Otte (daniel.otte@rub.de)
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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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*/
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/*
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* File: arcfour.h
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* Author: Daniel Otte
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* Date: 2006-06-07
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* License: GPLv3+
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* Description: Implementation of the ARCFOUR (RC4 compatible) stream cipher algorithm.
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*/
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/**
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* \file arcfour.h
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* \author Daniel Otte
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* \date 2006-06-07
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* \license GPLv3+
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* \brief Implementation of the ARCFOUR (RC4 compatible) stream cipher algorithm.
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*
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* This header file defines the interface of the ARCFOUR cipher implementation.
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*
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* This implementation aims to be compatible with the ARCFOUR description
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* available at
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* http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt
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*/
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#ifndef ARCFOUR_H_
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#define ARCFOUR_H_
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#include <stdint.h>
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/** \typedef arcfour_ctx_t
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* \brief type for arcfour context
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*
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* A variable of this type may contain a complete ARCFOUR context.
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* The context is used to store the state of the cipher and gets
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* created by the arcfour_init(arcfour_ctx_t *c, uint8_t *key, uint8_t length_B)
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* function. The context is of the fixed size of 258 bytes
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*/
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/** \struct arcfour_ctx_st
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* \brief base for ::arcfour_ctx_t
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*
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* The struct holds the two indices and the S-Box
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*/
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typedef struct arcfour_ctx_st {
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uint8_t i,j;
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uint8_t s[256];
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} arcfour_ctx_t;
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/** \fn void arcfour_init(const void *key, uint8_t length_B, arcfour_ctx_t *ctx)
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* \brief setup a context with a key
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*
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* This function sets up a ::arcfour_ctx_t context using
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* the supplied key of the given length.
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* \param ctx pointer to the context
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* \param key pointer to the key
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* \param length_B length of the key in bytes (between 1 and 255)
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*/
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void arcfour_init(const void *key, uint8_t length_B, arcfour_ctx_t *ctx);
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/** \fn uint8_t arcfour_gen(arcfour_ctx_t *ctx)
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* \brief generates a byte of keystream
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*
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* This function generates the next byte of keystream
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* from the supplied ::arcfour_ctx_t context which is updated accordingly
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*
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* \param ctx pointer to the context
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* \return byte of keystream
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*/
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uint8_t arcfour_gen(arcfour_ctx_t *ctx);
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#endif
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