SECCON 2015 の Reverse Engineering Hardare 2 の回路を再現した

reverse_engineering_hardware_2.cpp

#include <fstream>


static unsigned char setValue( unsigned char value )
{
    unsigned char v = value + 3;
    if ( ( v & 0x0f ) == 0x0f )
        v += 0x10;
    return
        ( ( v & 0xfe ) >> 1 ) |
        ( ( v & 0x01 ) << 7 );
}


int main()
{
	const unsigned char encrypted[] =
	{
		0x1F,0x0A,0x4A,0xAA,0xCE,0x3C,0xAD,0xAA,0x87,0x46,0x42,0xFF,0x2A,0x40,0x15,0x07,
		0x46,0x01,0x73,0xDC,0x00,0x2E,0x79,0x4B,0x5F,0x61,0x7E,0x9D,0x3A,0xDA,0x2F,0xD8,
		0x6F,0x66,0x5E,0x1A,0x14,0x18,0x55,0x7D,0x93,0xC2,0x64,0x79,0xA4,0x72,0x95,0x40,
		0xB6,0xE5,0x21,0x3E,0x88,0xB7,0xCE,0xE1,0x78,0x4D,0x29,0x60,0x75,0x59,0xDD,0x1C,
		0x9C,0xD7,0x6D
	};

	unsigned char a = 0;
	std::ofstream out( "out.bin" , std::ios::out | std::ios::binary );
	for ( auto v : encrypted )
	{
        out << static_cast<char>( v ^ a );
        a = setValue(a);
	}

    return 0;
}