That is roughly how Bitcoin full nodes already work, although with one necessary change.
Bitcoin, on the protocol degree, has no notion of addresses, and does not work in an “account” primarily based vogue, for privateness causes. As an alternative, it makes use of a “UTXO mannequin” (unspent transaction output). The concept the state of ledger is a set of UTXOs, which you’ll consider as “cash”. Each transaction consumes sure particular, referenced cash of their entirety, after which creates new cash whose mixed worth doesn’t exceed the consumed cash’ worth. Every coin has an identifier, an quantity, and a locking script which determines the situations below which it may be spent (as a simplification, you may consider locking scripts and addresses as the identical factor). Nonetheless, cash all have their very own id, and will not be recognized by their script/deal with. With a view to create a transaction, it’s important to specify precisely which cash you are spending. The deal with simply controls what signature is predicted to signal for it, however there is no such thing as a stability per deal with on the protocol degree, simply cash.
The rationale for this UTXO mannequin is privateness: account primarily based fashions (the place the rule is that sending accounts have adequate funds obtainable) encourage reuse, as a result of reusing the identical account is cheaper (each economically and computationally) than creating new accounts for every receipt. Such reuse is horrible for privateness, because it makes it trivial to hyperlink transactions of the identical consumer collectively. Usually, we would like a system the place performing in a extra non-public method shouldn’t be dearer than not doing so. In a UTXO mannequin, reusing addresses is simply as expensive as utilizing a brand new deal with for every receipt, satisfying that property (there are after all different privateness leaks too, not coated by deal with reuse).
So, with that out of the best way, the equal of the “deal with: stability” listing you think about, is definitely a “coin: worth, script” listing, and it’s referred to as the “UTXO set”.
Bitcoin full nodes really don’t use the blockchain for something throughout validation. They obtain all blocks, test them towards the UTXO set (e.g. checking that each one cash consumed by the transactions within the block nonetheless exist), then replace the UTXO set (eradicating spent cash, and including newly created cash), after which transfer on to the subsequent block. Some nodes do maintain the block after processing round, however it’s simply in order that they’ll present to different nodes who ask for it; they do not use it for validation of future blocks, that simply wants the UTXO set. So-called pruned nodes do not maintain blocks round after validation.
The present UTXO set is a couple of GB when saved on disk, and that’s the minimal wanted to run a node. It’s far decrease than storing the entire blockchain, which is a couple of hundred GB.
Now, as a way to totally validate with out trusting their friends, nodes do have to obtain and course of all blocks, in order that they’ll construct up the UTXO set. It is in principle attainable to simply get the UTXO set from one other node, however that does contain trusting that that UTXO set is right. There isn’t a P2P protocol for doing so, although there’s ongoing work (referred to as “assumeutxo”) to allow one thing alongside these strains.