Monero Community Criticizes ‘Mordinals’ Over Privacy Concerns

What are Mordinals?

In January, Casey Rodarmor launched the Bitcoin Ordinals protocol, allowing anyone to inscribe arbitrary data alongside Bitcoin transactions. This enables users to attach data to a single satoshi. The Ordinals protocol keeps track of these satoshis, the linked data and their unique identifiers, facilitating nonfungible tokens on the network.

Mordinals are essentially a modified implementation of Ordinals on the Monero blockchain. While Ordinals require data to be stored in the “witness” part of a Bitcoin transaction, Mordinals use the “tx_extra” field that exists within each Monero transaction. This has technically been possible on Monero since 2014, but until now, there has been no support for it.

Criticisms against Mordinals

Criticisms against Mordinals closely mirror those levied against its Bitcoin counterpart, but with an additional focus on how it could impact Monero’s privacy. The Monero community values privacy above all else, and introducing NFTs on a network that strives to make its tokens as unremarkable as possible was never going to be easy.

• To protect user privacy, Monero transactions are signed using “ring signatures,” which bundle a transaction with a set of fake ones. If an attacker with enough capital flooded Monero blocks with Mordinals, it would be trivial to distinguish actual transactions from the dummy NFTs. This is a genuine concern for Monero.
• In 2020, the United States Internal Revenue Service offered a $625,000 bounty to anyone who could help track Monero transactions, so it’s safe to say there’s a market for conducting such attacks.
• Another common criticism against Mordinals is its potential impact on decentralization. As blocks get bigger, storage requirements for nodes increase, disincentivizing smaller nodes from staying online.

Are Mordinals really that bad?

Monero, unlike Bitcoin, has a dynamic block size, and the idea that Mordinals might cause the blockchain to expand abnormally is a legitimate concern in the Monero community. However, looking at on-chain metrics, it doesn’t appear that blocks are growing wildly faster.

While Mordinals’ impact on privacy shouldn’t be taken lightly, some argue that the risks can be fixed through updates. Limiting the size of the tx_extra field within Monero transactions to 256 bytes could significantly increase the attack cost of flooding the network with dummy transactions while providing flexibility for future use cases.

According to Apollo Greed, CEO of gaming merchant service firm QGlobe Games, there’s enormous potential for privacy-conscious NFTs in protecting financial data while selling in-game assets.

What’s next for Mordinals

In a Twitter thread, Cake Wallet vice president Justin Ehrenhofer suggested limiting the size of the tx_extra field. The community appears to have partially aligned itself with Ehrenhofer, having since merged a patch to limit tx_extra’s size to 1,060 bytes. This makes it much harder for someone to attack the network.