private Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry)
{
if ((entry.Version < 50) || ((entry.Flags & 0x40) == 0))
{
PkzipClassicManaged managed = new PkzipClassicManaged();
OnKeysRequired(entry.Name);
if (!HaveKeys)
{
throw new ZipException("No password available for encrypted stream");
}
CryptoStream classicCryptoStream
= new CryptoStream(baseStream, managed.CreateDecryptor(key, null), CryptoStreamMode.Read);
CheckClassicPassword(classicCryptoStream, entry);
return classicCryptoStream;
}
if (entry.Version != 0x33)
{
throw new ZipException("Decryption method not supported");
}
OnKeysRequired(entry.Name);
if (!HaveKeys)
{
throw new ZipException("No password available for AES encrypted stream");
}
int aESSaltLen = entry.AESSaltLen;
byte[] buffer = new byte[aESSaltLen];
int num2 = baseStream.Read(buffer, 0, aESSaltLen);
if (num2 != aESSaltLen)
{
throw new ZipException(string.Concat(new object[] { "AES Salt expected ", aESSaltLen, " got ", num2 }));
}
byte[] buffer2 = new byte[2];
baseStream.Read(buffer2, 0, 2);
int blockSize = entry.AESKeySize / 8;
ZipAESTransform transform = new ZipAESTransform(rawPassword_, buffer, blockSize, false);
byte[] pwdVerifier = transform.PwdVerifier;
if ((pwdVerifier[0] != buffer2[0]) || (pwdVerifier[1] != buffer2[1]))
{
throw new Exception("Invalid password for AES");
}
return new ZipAESStream(baseStream, transform, CryptoStreamMode.Read);
}
private Stream CreateAndInitEncryptionStream(Stream baseStream, ZipEntry entry)
{
CryptoStream stream = null;
if ((entry.Version < 50) || ((entry.Flags & 0x40) == 0))
{
PkzipClassicManaged managed = new PkzipClassicManaged();
OnKeysRequired(entry.Name);
if (!HaveKeys)
{
throw new ZipException("No password available for encrypted stream");
}
stream = new CryptoStream(new UncompressedStream(baseStream), managed.CreateEncryptor(key, null), CryptoStreamMode.Write);
if ((entry.Crc < 0L) || ((entry.Flags & 8) != 0))
{
WriteEncryptionHeader(stream, entry.DosTime << 0x10);
return stream;
}
WriteEncryptionHeader(stream, entry.Crc);
}
return stream;
}
private int InitialRead(byte[] destination, int offset, int count)
{
if (!CanDecompressEntry)
{
throw new ZipException("Library cannot extract this entry. Version required is (" + entry.Version.ToString() + ")");
}
if (entry.IsCrypted)
{
if (password == null)
{
throw new ZipException("No password set.");
}
PkzipClassicManaged managed = new PkzipClassicManaged();
byte[] rgbKey = PkzipClassic.GenerateKeys(ZipConstants.ConvertToArray(password));
base.inputBuffer.CryptoTransform = managed.CreateDecryptor(rgbKey, null);
byte[] outBuffer = new byte[12];
base.inputBuffer.ReadClearTextBuffer(outBuffer, 0, 12);
if (outBuffer[11] != entry.CryptoCheckValue)
{
throw new ZipException("Invalid password");
}
if (base.csize < 12L)
{
if ((entry.Flags & 8) == 0)
{
throw new ZipException(string.Format("Entry compressed size {0} too small for encryption", base.csize));
}
}
else
{
base.csize -= 12L;
}
}
else
{
base.inputBuffer.CryptoTransform = null;
}
if ((base.csize > 0L) || ((flags & 8) != 0))
{
if ((method == 8) && (base.inputBuffer.Available > 0))
{
base.inputBuffer.SetInflaterInput(base.inf);
}
internalReader = BodyRead;
return BodyRead(destination, offset, count);
}
internalReader = ReadingNotAvailable;
return 0;
}
