1 files changed, 39 insertions, 79 deletions

diff --git a/CPP/7zip/Crypto/ZipCrypto.cpp b/CPP/7zip/Crypto/ZipCrypto.cpp
index f5972c57..baaaf98e 100755
--- a/CPP/7zip/Crypto/ZipCrypto.cpp
+++ b/CPP/7zip/Crypto/ZipCrypto.cpp
@@ -15,114 +15,74 @@ namespace NZip {
 void CCipher::UpdateKeys(Byte b)
 {
   Keys[0] = CRC_UPDATE_BYTE(Keys[0], b);
-  Keys[1] += Keys[0] & 0xff;
-  Keys[1] = Keys[1] * 134775813L + 1;
+  Keys[1] = (Keys[1] + (Keys[0] & 0xFF)) * 0x8088405 + 1;
   Keys[2] = CRC_UPDATE_BYTE(Keys[2], (Byte)(Keys[1] >> 24));
 }
 
-void CCipher::SetPassword(const Byte *password, UInt32 passwordLen)
+STDMETHODIMP CCipher::CryptoSetPassword(const Byte *password, UInt32 passwordLen)
 {
-  Keys[0] = 305419896L;
-  Keys[1] = 591751049L;
-  Keys[2] = 878082192L;
-  for (UInt32 i = 0; i < passwordLen; i++)
+  Keys[0] = 0x12345678;
+  Keys[1] = 0x23456789;
+  Keys[2] = 0x34567890;
+  UInt32 i;
+  for (i = 0; i < passwordLen; i++)
     UpdateKeys(password[i]);
-}
-
-Byte CCipher::DecryptByteSpec()
-{
-  UInt32 temp = Keys[2] | 2;
-  return (Byte)((temp * (temp ^ 1)) >> 8);
-}
-
-Byte CCipher::DecryptByte(Byte b)
-{
-  Byte c = (Byte)(b ^ DecryptByteSpec());
-  UpdateKeys(c);
-  return c;
-}
-
-Byte CCipher::EncryptByte(Byte b)
-{
-  Byte c = (Byte)(b ^ DecryptByteSpec());
-  UpdateKeys(b);
-  return c;
-}
-
-void CCipher::DecryptHeader(Byte *buf)
-{
-  for (unsigned i = 0; i < kHeaderSize; i++)
-    buf[i] = DecryptByte(buf[i]);
-}
-
-void CCipher::EncryptHeader(Byte *buf)
-{
-  for (unsigned i = 0; i < kHeaderSize; i++)
-    buf[i] = EncryptByte(buf[i]);
-}
-
-STDMETHODIMP CEncoder::CryptoSetPassword(const Byte *data, UInt32 size)
-{
-  _cipher.SetPassword(data, size);
+  for (i = 0; i < 3; i++)
+    Keys2[i] = Keys[i];
   return S_OK;
 }
 
-STDMETHODIMP CEncoder::CryptoSetCRC(UInt32 crc)
+STDMETHODIMP CCipher::Init()
 {
-  _crc = crc;
   return S_OK;
 }
 
-STDMETHODIMP CEncoder::Init()
+Byte CCipher::DecryptByteSpec()
 {
-  return S_OK;
+  UInt32 temp = Keys[2] | 2;
+  return (Byte)((temp * (temp ^ 1)) >> 8);
 }
 
-HRESULT CEncoder::WriteHeader(ISequentialOutStream *outStream)
+HRESULT CEncoder::WriteHeader(ISequentialOutStream *outStream, UInt32 crc)
 {
-  Byte header[kHeaderSize];
-  g_RandomGenerator.Generate(header, kHeaderSize - 2);
-
-  header[kHeaderSize - 1] = Byte(_crc >> 24);
-  header[kHeaderSize - 2] = Byte(_crc >> 16);
-
-  _cipher.EncryptHeader(header);
-  return WriteStream(outStream, header, kHeaderSize);
+  Byte h[kHeaderSize];
+  g_RandomGenerator.Generate(h, kHeaderSize - 2);
+  h[kHeaderSize - 1] = (Byte)(crc >> 24);
+  h[kHeaderSize - 2] = (Byte)(crc >> 16);
+  RestoreKeys();
+  Filter(h, kHeaderSize);
+  return WriteStream(outStream, h, kHeaderSize);
 }
 
 STDMETHODIMP_(UInt32) CEncoder::Filter(Byte *data, UInt32 size)
 {
-  UInt32 i;
-  for (i = 0; i < size; i++)
-    data[i] = _cipher.EncryptByte(data[i]);
-  return i;
-}
-
-STDMETHODIMP CDecoder::CryptoSetPassword(const Byte *data, UInt32 size)
-{
-  _cipher.SetPassword(data, size);
-  return S_OK;
+  for (UInt32 i = 0; i < size; i++)
+  {
+    Byte b = data[i];
+    data[i] = (Byte)(b ^ DecryptByteSpec());;
+    UpdateKeys(b);
+  }
+  return size;
 }
 
 HRESULT CDecoder::ReadHeader(ISequentialInStream *inStream)
 {
-  Byte header[kHeaderSize];
-  RINOK(ReadStream_FAIL(inStream, header, kHeaderSize));
-  _cipher.DecryptHeader(header);
-  return S_OK;
-}
-
-STDMETHODIMP CDecoder::Init()
-{
+  Byte h[kHeaderSize];
+  RINOK(ReadStream_FAIL(inStream, h, kHeaderSize));
+  RestoreKeys();
+  Filter(h, kHeaderSize);
   return S_OK;
 }
 
 STDMETHODIMP_(UInt32) CDecoder::Filter(Byte *data, UInt32 size)
 {
-  UInt32 i;
-  for (i = 0; i < size; i++)
-    data[i] = _cipher.DecryptByte(data[i]);
-  return i;
+  for (UInt32 i = 0; i < size; i++)
+  {
+    Byte c = (Byte)(data[i] ^ DecryptByteSpec());
+    UpdateKeys(c);
+    data[i] = c;
+  }
+  return size;
 }
 
 }}