Quote from: Pieter Wuille on June 28, 2017, 09:55:20 PM

Quote from: aliashraf on June 28, 2017, 09:12:53 PM

A full node is capable to handle temporary chain splits and to choose the right sequence by checking for double spend and not the signatures.

That's a nonsensical security model. You're allowing an attacker to take anyone's money with invalid signatures, but not spend it twice? ...

Spending money twice is a long-term, permanent concern while proof of signature is just a short-term transient one, from the pov of the full/validator node, as long as it comes to incentives and interests in being and remaining a 'full node' capable of participating actively in consensus process.

Historically, this separation of concerns, has been the main invention of SegWit proposal from the first beginning and if you may bother and just check the documentation, you can find a lot of reference to it.

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Without the ability to validate signatures, you can effectively not validate any useful property of the system. If that's the model you want, it already exists, and it's called a light client. ...

Nah! current 'light clients' can do nothing about validation other than some trivial and formal checks. Post-SegWit ones , which I strongly believe will be the dominant nodes in the network, are capable of anything a traditional full node can do, including double-spend check.

Let's take a moment and chew it: Current light clients can't check UTXO and prevent double spends, post-SegWit 'semi-ligh' clients can. It is how SegWit encourages this kind of nodes and leaves no incentive to remain a prehistoric fat and resource consuming dinosaur. Clear?

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All SegWit does in this regard is reducing the bandwidth for such nodes. It doesn't change the requirements for nodes that do need to validate.

Yes it does! The requirements to validate the integrity of the blocks will be changed radically.

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5- March 2028: The court issues a verdict: "As there is no electronic signature proof 'attached' to the transaction

There is just as much proof in SegWit transactions as in others. The only difference is that it does not contribute to the txid. ...

That 'only' difference is a huge one Roll Eyes

When something is discarded from SHA2 process and txId, it is no longer necessary for validating the integrity of the hashing process and the block header and we just need UTXO to check double spend and become a full node ... Oops! we got a validator node (in your terminology) without any obligation to store the signatures for future use.