internal bool CryptSectionXts(bool encrypt, byte[] key, uint headerId, ulong offset, ulong length)
{
var startPage = XvdMath.OffsetToPageNumber(offset - UserDataOffset);
ulong numPages = XvdMath.BytesToPages(length);
// Pre-read data unit numbers to minimize needing to seek around the file
List <uint> dataUnits = null;
if (IsDataIntegrityEnabled)
{
dataUnits = new List <uint>();
for (uint page = 0; page < numPages; page++)
{
// fetch dataUnit from hash table entry for this page
// TODO: seems we'll have to insert dataUnit when re-adding hashtables...
// last 4 bytes of hash entry = dataUnit
_io.Stream.Position = (long)CalculateHashEntryOffsetForBlock(startPage + page, 0) + 0x14;
dataUnits.Add(_io.Reader.ReadUInt32());
}
}
var tweakAesKey = new byte[0x10];
var dataAesKey = new byte[0x10];
var tweak = new byte[0x10];
// Split tweak- / Data AES key
Array.Copy(key, tweakAesKey, 0x10);
Array.Copy(key, 0x10, dataAesKey, 0, 0x10);
// Copy VDUID and header Id as tweak
var headerIdBytes = BitConverter.GetBytes(headerId);
Array.Copy(Header.VDUID, 0, tweak, 0x8, 0x8);
Array.Copy(headerIdBytes, 0, tweak, 0x4, 0x4);
var cipher = new AesXtsTransform(tweak, dataAesKey, tweakAesKey, encrypt);
// Perform crypto!
_io.Stream.Position = (long)offset;
for (uint page = 0; page < numPages; page++)
{
var transformedData = new byte[PAGE_SIZE];
var pageOffset = _io.Stream.Position;
var origData = _io.Reader.ReadBytes((int)PAGE_SIZE);
cipher.TransformDataUnit(origData, 0, origData.Length, transformedData, 0, dataUnits?[(int)page] ?? page);
_io.Stream.Position = pageOffset;
_io.Writer.Write(transformedData);
}
return(true);
}
public bool VerifyXvcHash(bool rehash = false)
{
if (!IsXvcFile)
{
return(true);
}
ulong hashTreeSize = HashTreePageCount * PAGE_SIZE;
var ms = new MemoryStream();
var msIo = new IO(ms);
msIo.Writer.WriteStruct(XvcInfo);
// fix region headers to match pre-hashtable
for (int i = 0; i < XvcInfo.RegionCount; i++)
{
var region = RegionHeaders[i];
region.Hash = 0;
if (IsDataIntegrityEnabled)
{
if (HashTreeOffset >= region.Offset && region.Offset + region.Length > HashTreeOffset)
{
region.Length -= hashTreeSize;
}
else if (region.Offset > HashTreeOffset)
{
region.Offset -= hashTreeSize;
}
}
msIo.Writer.WriteStruct(region);
}
for (int i = 0; i < XvcInfo.UpdateSegmentCount; i++)
{
var segment = UpdateSegments[i];
var hashTreeEnd = XvdMath.BytesToPages(HashTreeOffset) + HashTreePageCount;
if (segment.PageNum >= hashTreeEnd)
{
segment.PageNum -= (uint)HashTreePageCount;
}
segment.Hash = 0;
msIo.Writer.WriteStruct(segment);
}
if (RegionSpecifiers != null)
{
for (int i = 0; i < XvcInfo.RegionSpecifierCount; i++)
{
msIo.Writer.WriteStruct(RegionSpecifiers[i]);
}
}
if (Header.XvcDataLength > msIo.Stream.Length)
{
msIo.Stream.SetLength(Header.XvcDataLength);
}
if (IsDataIntegrityEnabled)
{
// remove hash table offset from the special regions
if (XvcInfo.InitialPlayOffset > HashTreeOffset)
{
msIo.Stream.Position = 0xD28;
msIo.Writer.Write(XvcInfo.InitialPlayOffset - hashTreeSize);
}
if (XvcInfo.PreviewOffset > HashTreeOffset)
{
msIo.Stream.Position = 0xD40;
msIo.Writer.Write(XvcInfo.PreviewOffset - hashTreeSize);
}
}
byte[] xvcData = ms.ToArray();
msIo.Dispose();
byte[] hash = HashUtils.ComputeSha256(xvcData);
bool isValid = Header.OriginalXvcDataHash.IsEqualTo(hash);
if (rehash)
{
Header.OriginalXvcDataHash = hash;
}
return(isValid); //todo: investigate why this gets the correct hash for dev XVCs but fails for retail ones, might be to do with retail XVC data having a content ID that doesn't match with VDUID/UDUID
}
