Zcash developers target January for quantum-resistant signatures on the pool holding 70% of ZEC

A standard transparent Zcash address keeps its public key behind a hash until the owner spends. Spending publishes the key, and sending the remaining coins to a new address shields them with a different key that is still unpublished ^[7]. The January work is aimed at the moment of spending. The network would check a hash-based signature, so forging an approval would mean defeating the hashes, and a breakthrough against today's wallet keys would not automatically break the replacement ^[5]. "Our team plans for post-quantum signature opcodes to land in Zcash in January," Roman Akhtariev wrote in an engineering post for Zakura ^[3]. Zakura is one of the programs that runs the Zcash network and validates its transactions ^[11].

The fresh-address habit costs something on the privacy side. A holder who spreads savings across 10 addresses still needs 10 balances, and a typical wallet asks a server for those records ^[8]. That request gives the server a way to connect addresses that look unrelated on the chain ^[8]. Zakura's lookup tool uses private information retrieval, in which a database returns a record without learning which one was requested. The payments stay public, but the server is not handed a readable list of the wallet's addresses ^[9].

CoinDesk counted 11.96 million of the 16.98 million issued ZEC in the transparent pool on Thursday, using ZecStats data ^[2]. The share works out to 70.4% ^[12]. At Thursday's closing price the transparent pool is worth about $14.2 billion, and the 5.02 million coins outside it about $5.9 billion ^[16][13][17]. Both figures apply one day's close to the whole issued supply, so they are prices, and they move with the coin ^[16][17].

January can go differently in a few ways. The opcodes can land on schedule while activation slips, because the network has not confirmed a date ^[4]. The post, as CoinDesk reported it, does not say how existing transparent balances come under the new signatures. If holders have to spend into them, the covered share grows only as fast as coins move. And the threat behind the deadline is still a worst case: no practical attack on wallet keys has been demonstrated ^[10][15].

I think the 70% describes the pool the January code is written for, and the share of supply actually covered in January will be smaller. The order of work does follow the coins, with both new tools built for the public side and shielded payments left to separate safeguards ^[1][9]. The view is wrong if the network activates the opcodes in or near January and existing transparent balances fall under the new signatures without each holder moving coins.