private unsafe void WriteIntegrityTable()
{
_file.Position = Header.IntegrityTable.OffsetInWim;
foreach (XElement range in XmlEsdMetadata.Descendants("RANGE"))
{
int rangeLength = int.Parse(range.Attribute("Bytes").Value);
long rangeOffset = long.Parse(range.Attribute("Offset").Value);
long chunkStart = rangeOffset - sizeof(WimHeader);
long chunkStartNum = chunkStart / IntegrityTable.Header.ChunkSize;
long chunkEnd = rangeOffset + rangeLength - sizeof(WimHeader);
long chunkEndNum = chunkEnd / IntegrityTable.Header.ChunkSize;
using (SHA1 sha = SHA1.Create())
{
for (long i = chunkStartNum; i <= chunkEndNum; i++)
{
_file.Position = sizeof(WimHeader) + i * IntegrityTable.Header.ChunkSize;
int chunkSize = _file.Position + IntegrityTable.Header.ChunkSize > Header.XmlData.OffsetInWim
? (int)(Header.XmlData.OffsetInWim - _file.Position)
: (int)IntegrityTable.Header.ChunkSize;
byte[] data = _reader.ReadBytes(chunkSize);
IntegrityTable.Hashes[i] = sha.ComputeHash(data, 0, data.Length);
}
}
}
_file.Position = Header.IntegrityTable.OffsetInWim;
byte[] bItHeader = new byte[sizeof(IntegrityTableHeader)];
IntegrityTableHeader ith = IntegrityTable.Header;
Marshal.Copy((IntPtr)(&ith), bItHeader, 0, bItHeader.Length);
_writer.Write(bItHeader);
foreach (byte[] b in IntegrityTable.Hashes)
{
_writer.Write(b);
}
}
public void DecryptEsd()
{
XmlEsdMetadata = XmlMetadata.Root?.Element("ESD");
if (XmlEsdMetadata == null)
{
throw new UnencryptedImageException();
}
string b64AesKey = XmlEsdMetadata.Element("KEY")?.Value;
if (string.IsNullOrEmpty(b64AesKey))
{
throw new NoImageKeyException();
}
byte[] bAesKey = Convert.FromBase64String(b64AesKey);
bool success = false;
foreach (byte[] cryptoKey in from k in CryptoKey.Keys
orderby Math.Abs(k.FirstBuild - BuildNumber)
select k.Key)
{
try
{
using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
{
rsa.ImportCspBlob(cryptoKey);
bAesKey = rsa.Decrypt(bAesKey, true);
}
}
catch (CryptographicException)
{
continue;
}
success = true;
break;
}
if (!success)
{
throw new NoValidCryptoKeyException();
}
foreach (XElement range in XmlEsdMetadata.Descendants("RANGE"))
{
int rangeLength = int.Parse(range.Attribute("Bytes").Value);
long rangeOffset = long.Parse(range.Attribute("Offset").Value);
_file.Position = rangeOffset;
int bEncryptedSize = (rangeLength / 16 + 1) * 16;
byte[] bEncrypted = _reader.ReadBytes(bEncryptedSize);
using (AesCryptoServiceProvider aesCipher = new AesCryptoServiceProvider
{
Key = bAesKey,
IV = Convert.FromBase64String("AAAAAAAAAAAAAAAAAAAAAA=="),
Mode = CipherMode.CBC,
Padding = PaddingMode.None
})
using (MemoryStream msEncrypted = new MemoryStream(bEncrypted))
using (CryptoStream strCrypto = new CryptoStream(msEncrypted, aesCipher.CreateDecryptor(), CryptoStreamMode.Read))
{
byte[] bDecrypted = new byte[bEncryptedSize - 16];
strCrypto.Read(bDecrypted, 0, bDecrypted.Length);
_file.Position = rangeOffset;
_file.Write(bDecrypted, 0, bDecrypted.Length);
_file.Flush();
}
}
XmlEsdMetadata.Remove();
WriteXmlMetadata();
WriteIntegrityTable();
WriteWimHeader();
}
