Zcash Plans Quantum-Resistant Upgrade for January

Zcash developers plan to add hash-based signature opcodes in January 2027 to help the network resist attacks from future quantum computers. The upgrade has no confirmed date for activation across the network and will initially apply only to transparent payments.

Zakura, a team that develops and operates Zcash node software, outlined the plan in an engineering post. Zakura engineer Roman Akhtariev wrote that the team plans for “post-quantum signature opcodes to land in Zcash in January.”

The opcodes would allow Zcash to verify signatures based on the Winternitz One-Time Signature, or WOTS, scheme. Current cryptocurrency wallets commonly use elliptic-curve signatures. Hash-based signatures instead use values derived from secret data and are designed to withstand attacks that could eventually break elliptic-curve keys.

The first version would cover Zcash’s transparent payment pool, where transaction details are visible and the system works similarly to Bitcoin. About 11.96 million of the 16.98 million ZEC in circulation were held in the transparent pool on Oct. 8, according to ZecStats data cited in the engineering post.

The development follows a warning from Ethereum researcher Justin Drake, who urged cryptocurrency holders to prepare for what he called “bunker mode.” In a worst-case scenario, Drake wrote that advances in artificial intelligence could help find ways around the mathematics protecting Bitcoin and Ether wallets “in months, not years.” ZEC closed at about $1,185 on the day of the warning, after falling about 11% over the previous week.

Zcash is also developing address rotation and a private-lookup tool intended to prevent wallets from revealing which addresses belong to the same user. An experimental “Private queries” setting is available in the Vizor wallet, with a broader release expected soon.

The January plan does not cover shielded payments, which conceal senders, recipients and transaction amounts. Zcash’s quantum-recovery design warns that an attacker could save encrypted payment records today and try to decrypt them after a future mathematical breakthrough. The risk is known as “harvest now, decrypt later.”

Zcash has not specified separate protections for shielded transactions. January remains a development target rather than a scheduled network upgrade, and no date has been set for activating the new opcodes across the network.