X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/c3963755b7bdb05523e694fbecca4dca2ad0112b..a66fca86b9f81e07161e89c101338968eda9d6c5:/client/loclass/cipherutils.c

diff --git a/client/loclass/cipherutils.c b/client/loclass/cipherutils.c
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+/*****************************************************************************
+ * This file is part of iClassCipher. It is a reconstructon of the cipher engine
+ * used in iClass, and RFID techology.
+ *
+ * The implementation is based on the work performed by
+ * Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and
+ * Milosch Meriac in the paper "Dismantling IClass".
+ *
+ * Copyright (C) 2014 Martin Holst Swende
+ *
+ * This is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with IClassCipher.  If not, see <http://www.gnu.org/licenses/>.
+ ****************************************************************************/
+
+#include "cipherutils.h"
+#include "../util.h"
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+/**
+ *
+ * @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn >
+ * @param stream
+ * @return
+ */
+bool headBit( BitstreamIn *stream)
+{
+	int bytepos = stream->position >> 3; // divide by 8
+	int bitpos = (stream->position++) & 7; // mask out 00000111
+	return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
+}
+/**
+ * @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn>
+ * @param stream
+ * @return
+ */
+bool tailBit( BitstreamIn *stream)
+{
+	int bitpos = stream->numbits -1 - (stream->position++);
+
+	int bytepos= bitpos >> 3;
+	bitpos &= 7;
+	return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
+}
+/**
+ * @brief Pushes bit onto the stream
+ * @param stream
+ * @param bit
+ */
+void pushBit( BitstreamOut* stream, bool bit)
+{
+	int bytepos = stream->position >> 3; // divide by 8
+	int bitpos = stream->position & 7;
+	*(stream->buffer+bytepos) |= (bit & 1) <<  (7 - bitpos);
+	stream->position++;
+	stream->numbits++;
+}
+
+/**
+ * @brief Pushes the lower six bits onto the stream
+ * as b0 b1 b2 b3 b4 b5 b6
+ * @param stream
+ * @param bits
+ */
+void push6bits( BitstreamOut* stream, uint8_t bits)
+{
+	pushBit(stream, bits & 0x20);
+	pushBit(stream, bits & 0x10);
+	pushBit(stream, bits & 0x08);
+	pushBit(stream, bits & 0x04);
+	pushBit(stream, bits & 0x02);
+	pushBit(stream, bits & 0x01);
+}
+
+/**
+ * @brief bitsLeft
+ * @param stream
+ * @return number of bits left in stream
+ */
+int bitsLeft( BitstreamIn *stream)
+{
+	return stream->numbits - stream->position;
+}
+/**
+ * @brief numBits
+ * @param stream
+ * @return Number of bits stored in stream
+ */
+int numBits(BitstreamOut *stream)
+{
+	return stream->numbits;
+}
+
+uint8_t reversebytes(uint8_t b) {
+	b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
+	b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
+	b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
+   return b;
+}
+void reverse_arraybytes(uint8_t* arr, size_t len)
+{
+	uint8_t i;
+	for( i =0; i< len ; i++)
+	{
+		arr[i] = reversebytes(arr[i]);
+	}
+}
+
+
+//-----------------------------
+// Code for testing below
+//-----------------------------
+
+
+int testBitStream()
+{
+	uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
+	uint8_t output [] = {0,0,0,0,0,0,0,0};
+	BitstreamIn in = { input, sizeof(input) * 8,0};
+	BitstreamOut out ={ output, 0,0}
+					  ;
+	while(bitsLeft(&in) > 0)
+	{
+		pushBit(&out, headBit(&in));
+		//printf("Bits left: %d\n", bitsLeft(&in));
+		//printf("Bits out: %d\n", numBits(&out));
+	}
+	if(memcmp(input, output, sizeof(input)) == 0)
+	{
+		printf("Bitstream test 1 ok\n");
+	}else
+	{
+		printf("Bitstream test 1 failed\n");
+		uint8_t i;
+		for(i = 0 ; i < sizeof(input) ; i++)
+		{
+			printf("IN %02x, OUT %02x\n", input[i], output[i]);
+		}
+		return 1;
+	}
+	return 0;
+}
+
+int testReversedBitstream()
+{
+	uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
+	uint8_t reverse [] = {0,0,0,0,0,0,0,0};
+	uint8_t output [] = {0,0,0,0,0,0,0,0};
+	BitstreamIn in = { input, sizeof(input) * 8,0};
+	BitstreamOut out ={ output, 0,0};
+	BitstreamIn reversed_in ={ reverse, sizeof(input)*8,0};
+	BitstreamOut reversed_out ={ reverse,0 ,0};
+
+	while(bitsLeft(&in) > 0)
+	{
+		pushBit(&reversed_out, tailBit(&in));
+	}
+	while(bitsLeft(&reversed_in) > 0)
+	{
+		pushBit(&out, tailBit(&reversed_in));
+	}
+	if(memcmp(input, output, sizeof(input)) == 0)
+	{
+		printf("Bitstream test 2 ok\n");
+	}else
+	{
+		printf("Bitstream test 2 failed\n");
+		uint8_t i;
+		for(i = 0 ; i < sizeof(input) ; i++)
+		{
+			printf("IN %02x, MIDDLE: %02x, OUT %02x\n", input[i],reverse[i], output[i]);
+		}
+		return 1;
+	}
+	return 0;
+}
+
+
+int testCipherUtils(void)
+{
+	int retval = 0;
+	retval |= testBitStream();
+	retval |= testReversedBitstream();
+	return retval;
+}