mirror of
https://github.com/RfidResearchGroup/proxmark3.git
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117 lines
3.6 KiB
C
117 lines
3.6 KiB
C
//-----------------------------------------------------------------------------
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// Borrowed initially from https://github.com/holiman/loclass
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// Copyright (C) 2014 Martin Holst Swende
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// Copyright (C) Proxmark3 contributors. See AUTHORS.md for details.
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//
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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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//
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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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//
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// See LICENSE.txt for the text of the license.
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//-----------------------------------------------------------------------------
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// WARNING
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//
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// THIS CODE IS CREATED FOR EXPERIMENTATION AND EDUCATIONAL USE ONLY.
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//
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// USAGE OF THIS CODE IN OTHER WAYS MAY INFRINGE UPON THE INTELLECTUAL
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// PROPERTY OF OTHER PARTIES, SUCH AS INSIDE SECURE AND HID GLOBAL,
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// AND MAY EXPOSE YOU TO AN INFRINGEMENT ACTION FROM THOSE PARTIES.
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//
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// THIS CODE SHOULD NEVER BE USED TO INFRINGE PATENTS OR INTELLECTUAL PROPERTY RIGHTS.
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//-----------------------------------------------------------------------------
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// It is a reconstruction of the cipher engine used in iClass, and RFID techology.
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//
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// The implementation is based on the work performed by
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// Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and
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// Milosch Meriac in the paper "Dismantling IClass".
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//-----------------------------------------------------------------------------
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#include "optimized_cipherutils.h"
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#include <stdint.h>
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/**
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*
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* @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn >
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* @param stream
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* @return
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*/
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bool headBit(BitstreamIn_t *stream) {
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int bytepos = stream->position >> 3; // divide by 8
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int bitpos = (stream->position++) & 7; // mask out 00000111
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return (*(stream->buffer + bytepos) >> (7 - bitpos)) & 1;
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}
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/**
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* @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn>
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* @param stream
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* @return
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*/
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bool tailBit(BitstreamIn_t *stream) {
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int bitpos = stream->numbits - 1 - (stream->position++);
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int bytepos = bitpos >> 3;
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bitpos &= 7;
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return (*(stream->buffer + bytepos) >> (7 - bitpos)) & 1;
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}
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/**
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* @brief Pushes bit onto the stream
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* @param stream
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* @param bit
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*/
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void pushBit(BitstreamOut_t *stream, bool bit) {
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int bytepos = stream->position >> 3; // divide by 8
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int bitpos = stream->position & 7;
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*(stream->buffer + bytepos) |= (bit) << (7 - bitpos);
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stream->position++;
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stream->numbits++;
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}
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/**
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* @brief Pushes the lower six bits onto the stream
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* as b0 b1 b2 b3 b4 b5 b6
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* @param stream
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* @param bits
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*/
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void push6bits(BitstreamOut_t *stream, uint8_t bits) {
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pushBit(stream, bits & 0x20);
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pushBit(stream, bits & 0x10);
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pushBit(stream, bits & 0x08);
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pushBit(stream, bits & 0x04);
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pushBit(stream, bits & 0x02);
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pushBit(stream, bits & 0x01);
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}
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/**
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* @brief bitsLeft
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* @param stream
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* @return number of bits left in stream
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*/
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int bitsLeft(BitstreamIn_t *stream) {
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return stream->numbits - stream->position;
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}
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/**
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* @brief numBits
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* @param stream
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* @return Number of bits stored in stream
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*/
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void x_num_to_bytes(uint64_t n, size_t len, uint8_t *dest) {
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while (len--) {
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dest[len] = (uint8_t) n;
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n >>= 8;
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}
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}
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uint64_t x_bytes_to_num(uint8_t *src, size_t len) {
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uint64_t num = 0;
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while (len--) {
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num = (num << 8) | (*src);
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src++;
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}
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return num;
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}
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