public static PkwareTraditionalEncryptionData ForRead(string password, ZipFileEntry header,
byte[] encryptionHeader)
{
var encryptor = new PkwareTraditionalEncryptionData(password);
byte[] plainTextHeader = encryptor.Decrypt(encryptionHeader, encryptionHeader.Length);
if (plainTextHeader[11] != (byte)((header.Crc >> 24) & 0xff))
{
if (!FlagUtility.HasFlag(header.Flags, HeaderFlags.UsePostDataDescriptor))
{
throw new CryptographicException("The password did not match.");
}
if (plainTextHeader[11] != (byte)((header.LastModifiedTime >> 8) & 0xff))
{
throw new CryptographicException("The password did not match.");
}
}
return(encryptor);
}
private void LoadHeader(ZipFileEntry entryHeader, Stream stream)
{
if (FlagUtility.HasFlag(entryHeader.Flags, HeaderFlags.Encrypted))
{
if (!entryHeader.IsDirectory &&
entryHeader.CompressedSize == 0 &&
FlagUtility.HasFlag(entryHeader.Flags, HeaderFlags.UsePostDataDescriptor))
{
throw new NotSupportedException(
"TF.Common.SharpCompress cannot currently read non-seekable Zip Streams with encrypted data that has been written in a non-seekable manner.");
}
if (password == null)
{
throw new CryptographicException("No password supplied for encrypted zip.");
}
if (entryHeader.CompressionMethod != ZipCompressionMethod.WinzipAes)
{
byte[] buffer = new byte[12];
stream.Read(buffer, 0, 12);
entryHeader.PkwareTraditionalEncryptionData = PkwareTraditionalEncryptionData.ForRead(password,
entryHeader,
buffer);
entryHeader.CompressedSize -= 12;
}
else
{
#if PORTABLE || NETFX_CORE
throw new NotSupportedException("Cannot decrypt Winzip AES with Silverlight or WP7.");
#else
var data = entryHeader.Extra.Where(x => x.Type == ExtraDataType.WinZipAes).SingleOrDefault();
WinzipAesKeySize keySize = (WinzipAesKeySize)data.DataBytes[4];
byte[] salt = new byte[WinzipAesEncryptionData.KeyLengthInBytes(keySize) / 2];
byte[] passwordVerifyValue = new byte[2];
stream.Read(salt, 0, salt.Length);
stream.Read(passwordVerifyValue, 0, 2);
entryHeader.WinzipAesEncryptionData = new WinzipAesEncryptionData(keySize, salt, passwordVerifyValue,
password);
entryHeader.CompressedSize -= (uint)(salt.Length + 2);
#endif
}
}
if (entryHeader.IsDirectory)
{
return;
}
//if (FlagUtility.HasFlag(entryHeader.Flags, HeaderFlags.UsePostDataDescriptor))
//{
// entryHeader.PackedStream = new ReadOnlySubStream(stream);
//}
//else
//{
switch (mode)
{
case StreamingMode.Seekable:
{
entryHeader.DataStartPosition = stream.Position;
stream.Position += entryHeader.CompressedSize;
}
break;
case StreamingMode.Streaming:
{
entryHeader.PackedStream = stream;
}
break;
default:
{
throw new InvalidFormatException("Invalid StreamingMode");
}
}
//}
}
public PkwareTraditionalCryptoStream(Stream stream, PkwareTraditionalEncryptionData encryptor, CryptoMode mode)
{
this.encryptor = encryptor;
this.stream = stream;
this.mode = mode;
}