As a tribute to code developed in the early days of the Bitcoin network by creator Satoshi Nakamoto, Ordinals developer Taproot Wizards is launching a new collection of NFTs on the Bitcoin blockchain.

“‘OP_CAT’ is an ancient ‘op code’ in Bitcoin that was introduced by Satoshi in the first release but later disabled,” Taproots Wizards co-founder Udi Wertheimer told Decrypt. “OP_CAT is shorthand for ‘concatenate’ in nerd-speak; it’s just a way to put two strings of text together.”

Even though it was disabled, Wertheimer explained, the OP_CAT Bitcoin Improvement Proposal (BIP) enables what’s called “covenants,” allowing smart contracts and bridges to be built on Bitcoin. The potential of making Bitcoin quantum-resistant, thanks to OP_CAT, led to the idea of naming the collection Quantum Cats.

A Quantum Cat
Image: Taproot Wizards

The Quantum Cats Ordinals is a collection of 3,333 cat images minted using Ordinals Inscriptions. Named after the Bitcoin upgrade known as Taproot, Taproot Wizards said the Quantum Cats collection cost $66,000 to create, using a technique called Evolving Inscriptions.

“Essentially we inscribed, ahead of time, multiple versions of the cats, and they’ll evolve over time, alongside the evolution of the OP_CAT proposal process,” Wertheimer said. “It was expensive to inscribe because it’s a lot of data. It’s not just 3,333 cats; it’s multiple evolutions of each cat.”

In addition to being expensive, the Quantum Cats collection used 10MB of encrypted on-chain data. The capacity of a single Bitcoin block is 1MB.

“They’re encrypted so no one can see what future evolutions look like until they’re revealed, but we wanted all evolutions to be committed to ahead of time so that they evolve in predetermined ways,” Wertheimer said. “Once we inscribed them, we can’t affect the evolutions anymore; it’s all on-chain.”

According to Taproot Wizards, a special edition of the Ordinal called “Genesis Cat” by digital artist FAR is being auctioned at Sotheby’s from Friday until January 22.


Similar to Ethereum-based NFT art Ordinals Inscriptions are digital art for the Bitcoin blockchain. Over 50 million Ordinal Inscriptions have been minted since the protocol launched last January. Inscriptions on the Bitcoin blockchain include text, images, videos, meme coins, and video games. Last month, the popular Solana wallet, Phantom, added support for Bitcoin, Ordinals, and BRC-20 tokens.

“Without Bitcoin, there’d be no Solana, Ethereum, or Web3,” Phantom posted on Twitter Wednesday. “And for that, we’re forever grateful for Bitcoin and thrilled to launch it (in beta) on Phantom.”

Bitcoin purists and critics continue to rail against Ordinals, calling the digital artifacts “spam,” taking up space on the network. When asked what Wertheimer would say to Ordinals critics, he simply replied, “Thanks for hosting my JPEGs on your nodes.”

“There’s much more than meets the eye with Ordinals,” Taproot Wizards co-founder Eric Wall said. “Ordinals has brought a new art form that takes place inside the Bitcoin blocks themselves.”

In November, Taproot Wizards announced the raise of $7.5 million in funding led by venture capital firm Standard Crypto. The raise was joined by StarkWare, UTXO Management, Bitcoin Frontier Fund, Masterkey, and Newman Capital.

“Our methods may be unorthodox, but we’ll drag our peers kicking and screaming to the non-custodial, scalable future that we believe Bitcoin deserves,” Wall continued. “OP_CAT and the Quantum Cats collection, for us, is the centerpiece of that ambition.”

Edited by Ryan Ozawa.


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