p7zip/CPP/7zip/Crypto/Rar20Crypto.cpp
2017-10-11 12:35:36 +02:00

131 lines
3.4 KiB
C++

// Crypto/Rar20Crypto.cpp
#include "StdAfx.h"
#include "../../../C/7zCrc.h"
#include "../../../C/CpuArch.h"
#include "../../../C/RotateDefs.h"
#include "Rar20Crypto.h"
namespace NCrypto {
namespace NRar2 {
static const unsigned kNumRounds = 32;
static const Byte g_InitSubstTable[256] = {
215, 19,149, 35, 73,197,192,205,249, 28, 16,119, 48,221, 2, 42,
232, 1,177,233, 14, 88,219, 25,223,195,244, 90, 87,239,153,137,
255,199,147, 70, 92, 66,246, 13,216, 40, 62, 29,217,230, 86, 6,
71, 24,171,196,101,113,218,123, 93, 91,163,178,202, 67, 44,235,
107,250, 75,234, 49,167,125,211, 83,114,157,144, 32,193,143, 36,
158,124,247,187, 89,214,141, 47,121,228, 61,130,213,194,174,251,
97,110, 54,229,115, 57,152, 94,105,243,212, 55,209,245, 63, 11,
164,200, 31,156, 81,176,227, 21, 76, 99,139,188,127, 17,248, 51,
207,120,189,210, 8,226, 41, 72,183,203,135,165,166, 60, 98, 7,
122, 38,155,170, 69,172,252,238, 39,134, 59,128,236, 27,240, 80,
131, 3, 85,206,145, 79,154,142,159,220,201,133, 74, 64, 20,129,
224,185,138,103,173,182, 43, 34,254, 82,198,151,231,180, 58, 10,
118, 26,102, 12, 50,132, 22,191,136,111,162,179, 45, 4,148,108,
161, 56, 78,126,242,222, 15,175,146, 23, 33,241,181,190, 77,225,
0, 46,169,186, 68, 95,237, 65, 53,208,253,168, 9, 18,100, 52,
116,184,160, 96,109, 37, 30,106,140,104,150, 5,204,117,112, 84
};
void CData::UpdateKeys(const Byte *data)
{
for (unsigned i = 0; i < 16; i += 4)
for (unsigned j = 0; j < 4; j++)
Keys[j] ^= g_CrcTable[data[i + j]];
}
static inline void Swap(Byte &b1, Byte &b2)
{
Byte b = b1;
b1 = b2;
b2 = b;
}
void CData::SetPassword(const Byte *data, unsigned size)
{
Keys[0] = 0xD3A3B879L;
Keys[1] = 0x3F6D12F7L;
Keys[2] = 0x7515A235L;
Keys[3] = 0xA4E7F123L;
Byte psw[128];
memset(psw, 0, sizeof(psw));
if (size != 0)
{
if (size >= sizeof(psw))
size = sizeof(psw) - 1;
memcpy(psw, data, size);
}
memcpy(SubstTable, g_InitSubstTable, sizeof(SubstTable));
for (unsigned j = 0; j < 256; j++)
for (unsigned i = 0; i < size; i += 2)
{
unsigned n1 = (Byte)g_CrcTable[(psw[i] - j) & 0xFF];
unsigned n2 = (Byte)g_CrcTable[(psw[i + 1] + j) & 0xFF];
for (unsigned k = 1; (n1 & 0xFF) != n2; n1++, k++)
Swap(SubstTable[n1 & 0xFF], SubstTable[(n1 + i + k) & 0xFF]);
}
for (unsigned i = 0; i < size; i += 16)
EncryptBlock(psw + i);
}
void CData::CryptBlock(Byte *buf, bool encrypt)
{
Byte inBuf[16];
UInt32 A, B, C, D;
A = GetUi32(buf + 0) ^ Keys[0];
B = GetUi32(buf + 4) ^ Keys[1];
C = GetUi32(buf + 8) ^ Keys[2];
D = GetUi32(buf + 12) ^ Keys[3];
if (!encrypt)
memcpy(inBuf, buf, sizeof(inBuf));
for (unsigned i = 0; i < kNumRounds; i++)
{
UInt32 key = Keys[(encrypt ? i : (kNumRounds - 1 - i)) & 3];
UInt32 TA = A ^ SubstLong((C + rotlFixed(D, 11)) ^ key);
UInt32 TB = B ^ SubstLong((D ^ rotlFixed(C, 17)) + key);
A = C; C = TA;
B = D; D = TB;
}
SetUi32(buf + 0, C ^ Keys[0]);
SetUi32(buf + 4, D ^ Keys[1]);
SetUi32(buf + 8, A ^ Keys[2]);
SetUi32(buf + 12, B ^ Keys[3]);
UpdateKeys(encrypt ? buf : inBuf);
}
STDMETHODIMP CDecoder::Init()
{
return S_OK;
}
static const UInt32 kBlockSize = 16;
STDMETHODIMP_(UInt32) CDecoder::Filter(Byte *data, UInt32 size)
{
if (size == 0)
return 0;
if (size < kBlockSize)
return kBlockSize;
size -= kBlockSize;
UInt32 i;
for (i = 0; i <= size; i += kBlockSize)
DecryptBlock(data + i);
return i;
}
}}