The BIP-451 proposal was incorporated into the official Bitcoin repository and received an identification number on April 28th. Its creator, a developer known as “bubb1es”, is defining a standard protocol for wallets to permanently eliminate dust funds in his own initiative (dustin English) was created by a privacy sniffing attack.
A dust attack occurs when a malicious attacker sends a minimal amount of Bitcoin (so called dust because it’s small enough to barely cover the transaction fees). To the address you want to track. If a user ends up spending that Dust with their other funds, it will inadvertently reveal that those addresses belong to the same wallet, destroying the separation they were trying to maintain.
Modern wallets solve the problem by blocking these funds so they are never spent, but according to the BIP-451 proposal, that solution is incomplete. this is, Blocked funds remain on record Bitcoin’s Unspent Output Set (UTXO), a list that all nodes in the network must keep updated in order to validate transactions. As UTXO garbage accumulates without being removed, the list grows and increases the memory and storage requirements of the nodes supporting the network.
Additionally, according to the authors of BIP-451, future risks are not limited to network size. Update your software, reset your keys, or migrate to Another wallet may accidentally unlock those funds. Heirs who do not know the origin of the dust may spend them without knowing that it violates the privacy of the wallet.
BIP-451 suggests removing them rather than blocking them. According to the document, the mechanism consists of constructing a transaction that uses the full value of a Dust UTXO as a network fee, without transferring any value to the address.
The output of that transaction is OP_RETURN. This is a type of Bitcoin instruction that explicitly marks the recipient as non-existent. As a result, the link between addresses is not revealed and the UTXO disappears from the chain forever.
The viability of this mechanism was made possible by the reduction in the minimum retransmission fee introduced in Bitcoin Core 30, which brought it down to 0.1 Satoshi per virtual byte (sat/vB). This allows for a very small amount, enough to cover the fees of a delete transaction.
Risks recognized by developers themselves
According to the BIP-451 document, there are four specific risks to implementing the protocol into wallets.
First, if only one or a few wallets adopt it, deletion transactions create a digital footprint that identifies the user, which is the opposite problem to the one it is trying to solve. Second, if your wallet sends multiple delete transactions at the same time, it may turn out that they all belong to the same user.
Third, as network charges rise, Those transactions may remain unconfirmed If your commission goes down, you’ll need to resubmit.
Finally, and fourth, the process of signing deletion transactions can be confusing or unpleasant for users of wallets with multiple signers or hardware signing devices.
The practical utility of BIP-451 will ultimately depend on how many wallets adopt it and its inclusion in official Bitcoin repositories. This marks the beginning of a debate regarding its implementation or not.
