1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/win32/7zip/7z/CPP/7zip/Crypto/ZipCrypto.cpp	Sat Mar 03 10:31:27 2012 -0600
     1.3 @@ -0,0 +1,131 @@
     1.4 +// Crypto/ZipCrypto.cpp
     1.5 +
     1.6 +#include "StdAfx.h"
     1.7 +
     1.8 +extern "C"
     1.9 +{
    1.10 +#include "../../../C/7zCrc.h"
    1.11 +}
    1.12 +
    1.13 +#include "../Common/StreamUtils.h"
    1.14 +
    1.15 +#include "RandGen.h"
    1.16 +#include "ZipCrypto.h"
    1.17 +
    1.18 +namespace NCrypto {
    1.19 +namespace NZip {
    1.20 +
    1.21 +void CCipher::UpdateKeys(Byte b)
    1.22 +{
    1.23 +  Keys[0] = CRC_UPDATE_BYTE(Keys[0], b);
    1.24 +  Keys[1] += Keys[0] & 0xff;
    1.25 +  Keys[1] = Keys[1] * 134775813L + 1;
    1.26 +  Keys[2] = CRC_UPDATE_BYTE(Keys[2], (Byte)(Keys[1] >> 24));
    1.27 +}
    1.28 +
    1.29 +void CCipher::SetPassword(const Byte *password, UInt32 passwordLen)
    1.30 +{
    1.31 +  Keys[0] = 305419896L;
    1.32 +  Keys[1] = 591751049L;
    1.33 +  Keys[2] = 878082192L;
    1.34 +  for (UInt32 i = 0; i < passwordLen; i++)
    1.35 +    UpdateKeys(password[i]);
    1.36 +}
    1.37 +
    1.38 +Byte CCipher::DecryptByteSpec()
    1.39 +{
    1.40 +  UInt32 temp = Keys[2] | 2;
    1.41 +  return (Byte)((temp * (temp ^ 1)) >> 8);
    1.42 +}
    1.43 +
    1.44 +Byte CCipher::DecryptByte(Byte b)
    1.45 +{
    1.46 +  Byte c = (Byte)(b ^ DecryptByteSpec());
    1.47 +  UpdateKeys(c);
    1.48 +  return c;
    1.49 +}
    1.50 +
    1.51 +Byte CCipher::EncryptByte(Byte b)
    1.52 +{
    1.53 +  Byte c = (Byte)(b ^ DecryptByteSpec());
    1.54 +  UpdateKeys(b);
    1.55 +  return c;
    1.56 +}
    1.57 +
    1.58 +void CCipher::DecryptHeader(Byte *buf)
    1.59 +{
    1.60 +  for (unsigned i = 0; i < kHeaderSize; i++)
    1.61 +    buf[i] = DecryptByte(buf[i]);
    1.62 +}
    1.63 +
    1.64 +void CCipher::EncryptHeader(Byte *buf)
    1.65 +{
    1.66 +  for (unsigned i = 0; i < kHeaderSize; i++)
    1.67 +    buf[i] = EncryptByte(buf[i]);
    1.68 +}
    1.69 +
    1.70 +STDMETHODIMP CEncoder::CryptoSetPassword(const Byte *data, UInt32 size)
    1.71 +{
    1.72 +  _cipher.SetPassword(data, size);
    1.73 +  return S_OK;
    1.74 +}
    1.75 +
    1.76 +STDMETHODIMP CEncoder::CryptoSetCRC(UInt32 crc)
    1.77 +{
    1.78 +  _crc = crc;
    1.79 +  return S_OK;
    1.80 +}
    1.81 +
    1.82 +STDMETHODIMP CEncoder::Init()
    1.83 +{
    1.84 +  return S_OK;
    1.85 +}
    1.86 +
    1.87 +HRESULT CEncoder::WriteHeader(ISequentialOutStream *outStream)
    1.88 +{
    1.89 +  Byte header[kHeaderSize];
    1.90 +  g_RandomGenerator.Generate(header, kHeaderSize - 2);
    1.91 +
    1.92 +  header[kHeaderSize - 1] = Byte(_crc >> 24);
    1.93 +  header[kHeaderSize - 2] = Byte(_crc >> 16);
    1.94 +
    1.95 +  _cipher.EncryptHeader(header);
    1.96 +  return WriteStream(outStream, header, kHeaderSize);
    1.97 +}
    1.98 +
    1.99 +STDMETHODIMP_(UInt32) CEncoder::Filter(Byte *data, UInt32 size)
   1.100 +{
   1.101 +  UInt32 i;
   1.102 +  for (i = 0; i < size; i++)
   1.103 +    data[i] = _cipher.EncryptByte(data[i]);
   1.104 +  return i;
   1.105 +}
   1.106 +
   1.107 +STDMETHODIMP CDecoder::CryptoSetPassword(const Byte *data, UInt32 size)
   1.108 +{
   1.109 +  _cipher.SetPassword(data, size);
   1.110 +  return S_OK;
   1.111 +}
   1.112 +
   1.113 +HRESULT CDecoder::ReadHeader(ISequentialInStream *inStream)
   1.114 +{
   1.115 +  Byte header[kHeaderSize];
   1.116 +  RINOK(ReadStream_FAIL(inStream, header, kHeaderSize));
   1.117 +  _cipher.DecryptHeader(header);
   1.118 +  return S_OK;
   1.119 +}
   1.120 +
   1.121 +STDMETHODIMP CDecoder::Init()
   1.122 +{
   1.123 +  return S_OK;
   1.124 +}
   1.125 +
   1.126 +STDMETHODIMP_(UInt32) CDecoder::Filter(Byte *data, UInt32 size)
   1.127 +{
   1.128 +  UInt32 i;
   1.129 +  for (i = 0; i < size; i++)
   1.130 +    data[i] = _cipher.DecryptByte(data[i]);
   1.131 +  return i;
   1.132 +}
   1.133 +
   1.134 +}}