(For any audience, see SPV in Thin client security.)

Quote from: instagibbs on June 20, 2014, 03:22:52 PM

Ok, well again, this is still SPV-like security(block depth). That's the definition of the security model. Practically you might feel it's ok, but it's certainly a different security model than Bitcoin full node security.

In that it is using block-depth it is like SPV (this I already acknowledged in a previous post), but it is not the same because of the extra information in the UTXO, and it is not the same as rolling-root/ledger-block because the current root is guaranteed to not have any relevant transactions prior to it.

Please be specific. What does the attack scenario look like with UTXO and/or ledger-block, and why does it require the full transaction history?

The wiki seems to agree with me actually:

Quote

If such UOT hashes were included in the block chain, a client which shipped with a checkpoint block that had a UOT would only need to download blocks after the checkpoint. Moreover, once the client had downloaded those blocks and confirmed their UOTs, it could discard all but the most recent block containing a UOT.

https://en.bitcoin.it/wiki/Thin_Client_Security#Unused_Output_Tree_in_the_Block_chain_.28UOT.29

Edit: Although it is saying something slightly different (shipping clients with the full UTXO already intact, but I don't think that's necessary with rolling root. Would have to give it more thought, but might not be necessary for UTXO either. If there's a problem for UTXO, it could be fixed with a rolling-root type solution).