md2.cpp

MD2加密算法的具体实现

#include "stdafx.h"
#include "MD2.h"

static const U8 MD2_SBox[256] =
{
	0x29, 0x2E, 0x43, 0xC9, 0xA2, 0xD8, 0x7C, 0x01,
	0x3D, 0x36, 0x54, 0xA1, 0xEC, 0xF0, 0x06, 0x13,
	0x62, 0xA7, 0x05, 0xF3, 0xC0, 0xC7, 0x73, 0x8C,
	0x98, 0x93, 0x2B, 0xD9, 0xBC, 0x4C, 0x82, 0xCA,
	0x1E, 0x9B, 0x57, 0x3C, 0xFD, 0xD4, 0xE0, 0x16,
	0x67, 0x42, 0x6F, 0x18, 0x8A, 0x17, 0xE5, 0x12,
	0xBE, 0x4E, 0xC4, 0xD6, 0xDA, 0x9E, 0xDE, 0x49,
	0xA0, 0xFB, 0xF5, 0x8E, 0xBB, 0x2F, 0xEE, 0x7A,
	0xA9, 0x68, 0x79, 0x91, 0x15, 0xB2, 0x07, 0x3F,
	0x94, 0xC2, 0x10, 0x89, 0x0B, 0x22, 0x5F, 0x21,
	0x80, 0x7F, 0x5D, 0x9A, 0x5A, 0x90, 0x32, 0x27,
	0x35, 0x3E, 0xCC, 0xE7, 0xBF, 0xF7, 0x97, 0x03,
	0xFF, 0x19, 0x30, 0xB3, 0x48, 0xA5, 0xB5, 0xD1,
	0xD7, 0x5E, 0x92, 0x2A, 0xAC, 0x56, 0xAA, 0xC6,
	0x4F, 0xB8, 0x38, 0xD2, 0x96, 0xA4, 0x7D, 0xB6,
	0x76, 0xFC, 0x6B, 0xE2, 0x9C, 0x74, 0x04, 0xF1,
	0x45, 0x9D, 0x70, 0x59, 0x64, 0x71, 0x87, 0x20,
	0x86, 0x5B, 0xCF, 0x65, 0xE6, 0x2D, 0xA8, 0x02,
	0x1B, 0x60, 0x25, 0xAD, 0xAE, 0xB0, 0xB9, 0xF6,
	0x1C, 0x46, 0x61, 0x69, 0x34, 0x40, 0x7E, 0x0F,
	0x55, 0x47, 0xA3, 0x23, 0xDD, 0x51, 0xAF, 0x3A,
	0xC3, 0x5C, 0xF9, 0xCE, 0xBA, 0xC5, 0xEA, 0x26,
	0x2C, 0x53, 0x0D, 0x6E, 0x85, 0x28, 0x84, 0x09,
	0xD3, 0xDF, 0xCD, 0xF4, 0x41, 0x81, 0x4D, 0x52,
	0x6A, 0xDC, 0x37, 0xC8, 0x6C, 0xC1, 0xAB, 0xFA,
	0x24, 0xE1, 0x7B, 0x08, 0x0C, 0xBD, 0xB1, 0x4A,
	0x78, 0x88, 0x95, 0x8B, 0xE3, 0x63, 0xE8, 0x6D,
	0xE9, 0xCB, 0xD5, 0xFE, 0x3B, 0x00, 0x1D, 0x39,
	0xF2, 0xEF, 0xB7, 0x0E, 0x66, 0x58, 0xD0, 0xE4,
	0xA6, 0x77, 0x72, 0xF8, 0xEB, 0x75, 0x4B, 0x0A,
	0x31, 0x44, 0x50, 0xB4, 0x8F, 0xED, 0x1F, 0x1A,
	0xDB, 0x99, 0x8D, 0x33, 0x9F, 0x11, 0x83, 0x14
};

static U8 MD2_X[48], MD2_C[16], MD2_Buf[16];
static U8 MD2_Count;

void MD2_Init(void)
{
	U8 i;
	MD2_Count = 0;
	for (i=0; i<16; i++)
	{
		MD2_C[i] = MD2_Buf[i] = 0;
	}
	for (i=0; i<48; i++)
	{
		MD2_X[i] = 0;
	}
}

void MD2_Update(U8 *pData, U32 size)
{
	U8 Temp;
	U8 i, j;
	U8 PacketLen;

	while (size)
	{
		PacketLen = (size > (U8)(16 - MD2_Count)) ? (U8)(16 - MD2_Count) : (U8)size;
		for (i=MD2_Count; i<16; i++)
		{
			MD2_Buf[i] = *pData++;
		}
		MD2_Count += PacketLen;
		size -= PacketLen;
		
		if (MD2_Count == 0x10)
		{
			MD2_Count = 0;
			for (i=0; i<16; i++)
			{
				MD2_X[16+i] = MD2_Buf[i];
			}

			Temp = MD2_C[15];
			for (i=0; i<16; i++)
			{
				MD2_X[32+i] = MD2_X[16+i] ^ MD2_X[i];
				Temp = MD2_C[i] ^= (MD2_SBox[MD2_Buf[i] ^ Temp]);
			}
			
			Temp = 0;
			for (i=0; i<18; i++)
			{
				for (j=0; j<48; j++)
				{
					Temp = MD2_X[j] ^= MD2_SBox[Temp];
				}
				Temp = Temp + i;
			}
		}
	}
}

void MD2_Final(U8 *pResult, const U8 size)
{
	U8 i;
	U8 Padding[16];
	U8 PadLen;

	PadLen = 16 - MD2_Count;
	for (i=0; i<PadLen; i++)
	{
		Padding[i] = PadLen;
	}

	MD2_Update(Padding, PadLen);
	MD2_Update(MD2_C, 16);
	for (i=0; i<size; i++)
	{
		pResult[i] = MD2_X[i];
	}
}