private void DecryptHeader(ReadOnlySpan <byte> key, ref Package2Meta source, ref Package2Meta dest)
{
Buffer16 iv = source.HeaderIv;
Aes.DecryptCtr128(SpanHelpers.AsByteSpan(ref source), SpanHelpers.AsByteSpan(ref dest), key, iv);
// Copy the IV to the output because the IV field will be garbage after "decrypting" it
Unsafe.As <Package2Meta, Buffer16>(ref dest) = iv;
}
private static void DecryptKeyBlobs(KeySet s, IProgressReport logger = null)
{
var cmac = new AesCmac();
for (int i = 0; i < KeySet.UsedKeyBlobCount; i++)
{
if (s.KeyBlobKeys[i].IsZeros() || s.KeyBlobMacKeys[i].IsZeros() || s.EncryptedKeyBlobs[i].IsZeros())
{
continue;
}
Aes.CalculateCmac(cmac, s.EncryptedKeyBlobs[i].Bytes.Slice(0x10, 0xA0), s.KeyBlobMacKeys[i]);
if (!Utilities.SpansEqual <byte>(cmac, s.EncryptedKeyBlobs[i].Cmac))
{
logger?.LogMessage($"Warning: Keyblob MAC {i:x2} is invalid. Are SBK/TSEC key correct?");
}
Aes.DecryptCtr128(s.EncryptedKeyBlobs[i].Bytes.Slice(0x20), s.KeyBlobs[i].Bytes, s.KeyBlobKeys[i],
s.EncryptedKeyBlobs[i].Counter);
}
}