private static bool TryGetEncryptedPackage(Stream fileStream, CompoundDocument document, string password, out Stream stream)
{
var encryptedPackage = document.FindEntry(DirectoryEntryEncryptedPackage);
var encryptionInfo = document.FindEntry(DirectoryEntryEncryptionInfo);
if (encryptedPackage == null || encryptionInfo == null)
{
stream = null;
return(false);
}
var infoBytes = document.ReadStream(fileStream, encryptionInfo.StreamFirstSector, (int)encryptionInfo.StreamSize, encryptionInfo.IsEntryMiniStream);
var encryption = EncryptionInfo.Create(infoBytes);
if (encryption.VerifyPassword("VelvetSweatshop"))
{
// Magic password used for write-protected workbooks
password = "******";
}
else if (password == null || !encryption.VerifyPassword(password))
{
throw new InvalidPasswordException(Errors.ErrorInvalidPassword);
}
var secretKey = encryption.GenerateSecretKey(password);
var packageStream = document.CreateStream(fileStream, encryptedPackage.StreamFirstSector, (int)encryptedPackage.StreamSize, encryptedPackage.IsEntryMiniStream);
stream = encryption.CreateEncryptedPackageStream(packageStream, secretKey);
return(true);
}