I assume you mean writing some meta-data into the stronger block chain, that the weaker block chain could refer to as evidence. The hindrance is that decentralized block chains have no external reference point. There is no way to enforce that a particular block in one chain came before a block (nor within some # of blocks after a block) on another chain. Block chains are self-referential, and that is precisely why we need CLTV to implement decentralized exchange.
OK, so we are in agreement on most everything.
I want to better understand the above as it seems the main issue to prevent much stronger security. I apologize if I am asking kindergarten level questions on this, but I dont understand the external reference point impossibility. Please bear with me. I like concrete examples:
At noon, BTC block noon_txid appears. This is available to the entire bitcoin p2p network. At first it is a bit vulnerable to a reorg due to any pair of linked blocks would override it. After the next block, it would take 3 blocks to overtake, etc. So after 2 hours, we are past the timestamp variance and also have 10+ blocks protected by zillions of hashes.
ALL the altcoin chains can refer to this noon_txid. Let us call it noon_txid_inalt. I am pretty sure this is possible to do. And I am pretty sure that the presence of noon_txid_inalt proves that it came AFTER noon_txid. Please let us ignore odds of sha256 collisions.
In my previous post, I said bi-directional. So the BTC blockchain now gets the noon_txid_inalt and puts that into its blockchain (a bit past 2PM). call this the noon_altconfirm txid.
I claim that we now know that noon_txid happened before noon_txid_inalt which happened before noon_altconfirm txid. It looks like I can segregate blockchain events on different blockchains into definite categories of time ordering of "before" and "after"
What part of the above is insufficient to satisfy the requirements for the external reference?
James