Ethereum’s Secret Santa ZK Protocol: The Stealthy Game-Changer for On-Chain Privacy

Forget the elves—Ethereum's developers are building a different kind of holiday magic. The new Secret Santa protocol leverages zero-knowledge proofs to let users send private transactions, effectively wrapping gifts on the blockchain that no one else can peek inside.

The Privacy Push Hits Main Street

This isn't just academic. The push for on-chain privacy is a direct response to the glaring transparency of public ledgers—where every payment, trade, and NFT purchase is an open book for competitors, family members, and tax authorities to scrutinize. Secret Santa aims to cut through that by allowing selective disclosure.

How It Bypasses the Watchful Eyes

The protocol uses advanced cryptographic techniques to validate transactions without revealing sender, receiver, or amount details on the public chain. It creates a cryptographic proof that the transaction is valid, then posts only that proof. Think of it as confirming a package was delivered without announcing what's inside or who sent it.

A Nod to the TradFi Skeptics

Sure, Wall Street might scoff at a protocol named after a holiday party game—right before their own legacy systems get hacked and leak millions of social security numbers. The irony is thicker than a bank's fee schedule.

The move signals a pivotal shift. As regulatory scrutiny intensifies, tools for financial privacy aren't a niche desire; they're becoming a core utility. Ethereum's exploration here could set the standard, forcing every major chain to play catch-up or risk becoming a transparent fishbowl in a world demanding digital curtains.

Secret Santa deployment on Ethereum is possible, says Artem Chystiakov

Is it possible to play Secret Santa on-chain? Well, yes!

Here is a formal specification of the ZK Secret Santa protocol that can be implemented in Solidity. It preserves the full privacy of gift senders while maintaining the game's trustlessness and correctness.

Happy winter! pic.twitter.com/T3NC6eoty2

— Artem Chystiakov (@Arvolear) December 1, 2025

Artem Chystiakov, a Solidity engineer, brought his research to the spotlight on Monday through an Ethereum community forum post citing work he had published in January on arXiv. Chystiakov expressed his belief that deploying Secret Santa on-chain was possible. 

The engineer proposed a three-step Secret Santa algorithm that facilitates chain transactions between senders and receivers while maintaining the confidentiality of the involved parties. He explained that the algorithm could recreate the anonymous gift-exchange game on the Ethereum blockchain.

According to Chystiakov, the algorithm is decentralized and maintains a permutational derangement, which makes it implementable in Solidity. The dev suggested that the rollout faces distinct challenges, including Ethereum’s inability to allow computations privately.

His suggested solution to the challenge involves using a transaction “relayer” together with ZKP to hide the identities and addresses of Secret Santa participants. 

Chystiakov also explained in the community post that true randomness is unachievable on-chain but suggested that the choice of gift sender/receiver pair could be outsourced to the Secret Santa participants and verified via ZKP. The verification will ensure that no participant will select themselves, according to the developer. 

Chystiakov also described double voting as another challenge that could arise, but he proposed the concept of “nullifiers (blinders)” as the solution. The blinders will allow the protocol to verify participation without jeopardizing user anonymity.

The proposal’s proof-of-concept detailed that users register using their Ethereum addresses in a smart contract and retrieve a unique digital signature that will inhibit identical entries. The participants will then submit a random number to a shared list through the relayer.

The relayer will be responsible for broadcasting transactions, preventing participants from knowing which number belongs to which address. The shared numbers will also enable receivers to encrypt their delivery details, which can only be decrypted by their paired counterparts. 

The matching process will complete once a participant selects someone else’s random number, after which the protocol will reveal the receiver’s identity details, but only to the participant paired to them as their “Santa.” The rest of the network will not gain access to the pairing details and involved parties, thereby retaining the anonymity of the sender and receiver.

Ethereum heightens privacy protection for the network’s user activity

The news comes after Ethereum co-founder Vitalik Buterin recently referred to privacy as a hygiene rather than a network feature. Cryptopolitan reported that the remarks followed the compromise of several U.S. banking institutions by malicious attackers, who stole client information.

According to the report, the crypto pioneer outlined a plan for Ethereum to conceal transaction details and enhance privacy by using stealth addresses.

On November 18, the network introduced a privacy-oriented toolkit called Kohaku as part of its efforts to drive privacy evolution.

Buterin explained that the network divulges too much user personal data and urged developers to ensure users can achieve privacy protection. The toolkit comprises a wallet reference design, a lightweight client architecture, and a series of privacy protocols that work in sync to hide users’ data and validate the security of transactions.

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