Bitcoin Cash (BCH) faces a November 15 decision on quantum-resistant signatures

For Bitcoin Cash (BCH), a decision is due in three days. By November 15, 2026, it should be settled whether proposal CHIP-2026-06 goes into the network upgrade of May 2027. It would open the way for Bitcoin Cash to use signatures that even a powerful quantum computer cannot forge. According to The Quantum Insider, lock-in is scheduled for November 15 and mainnet activation for May 15, 2027. Both depend on the developers' ongoing review ending without objections.

The price is no help to the project right now. According to CoinGecko, Bitcoin Cash traded at $229.48 on Thursday, November 12, at around 1:50 a.m. CET, roughly 19 percent below its level seven days earlier. With a market capitalisation of $4.6 billion, BCH ranks 22nd among the largest cryptocurrencies.

CHIP-2026-06: what the quantum proposal changes for Bitcoin Cash

CHIP stands for Cash Improvement Proposal. That is the name Bitcoin Cash gives to proposed changes to its consensus rules, the rules by which every node classifies a transaction as valid or invalid. Proposal number 2026-06 was published on June 10, 2026 by a developer using the forum name mainnet_pat on the Bitcoin Cash Research forum.

Technically, the core is simple. The script opcodes that check signatures today are to be able to distinguish between several signature schemes in future. The first byte of the public key reveals which scheme applies. Behind it sits a registry. Today it contains only secp256k1, the elliptic curve on which current ECDSA and Schnorr signatures are based. Post-quantum schemes are to be added later.

A post-quantum scheme is a signature method whose security does not rest on mathematical problems that a quantum computer could solve with Shor's algorithm. Elliptic curves are among those vulnerable problems: anyone who knows the public key could, with a sufficiently large machine, compute the private key. Hash-based schemes, by contrast, are considered robust.

According to The Quantum Insider, the proposal also adds a new opcode called OP_SIGHASH. It pushes the signature hash of a transaction onto the stack, the fingerprint over which a signature is formed. The virtual machine computes this value during every signature check anyway. The proposal introduces no new cryptography, the trade publication quotes from the draft.

Lock-in on November 15: how the Bitcoin Cash upgrade timetable works

Bitcoin Cash changes its consensus rules on a fixed annual cycle. In the autumn, the developers of the node software commit to the proposals that will go into the next upgrade. The following May, the network activates the new rules. Lock-in is the cut-off date on which the selection is fixed. Whatever is not considered ready by then waits another year.

For CHIP-2026-06, The Quantum Insider gives exactly these dates: November 15, 2026 for lock-in and May 15, 2027 for activation. According to the same report, an implementation as a merge request for the Bitcoin Cash Node software already exists. Nothing is active yet, though. An open merge request is work in progress, not a network rule.

The proposal builds on the "Layla" upgrade of May 2026, which brought loops, functions and further bitwise operations to the scripting language. Since then, so-called Quantumroot vaults have already been running on mainnet, contracts that protect coins with an alternative, quantum-resistant signing path, The Quantum Insider reports. Today these contracts have to rebuild the signature hash themselves at considerable effort, which costs hundreds of bytes. With OP_SIGHASH, this part would shrink to a single two-byte opcode.

Hybrid keys: why two signatures have to be valid at once

The most interesting part of the draft is composite keys. A hybrid key combines two schemes with an AND condition, for example secp256k1 with a post-quantum scheme. A payment is only valid if both signatures are correct. Should one of the two schemes ever fall, the other continues to protect the coins.

The practical advantage lies in the address. According to the draft, hybrid and pure post-quantum keys can be spent from ordinary P2PKH outputs, the address type most wallets have used for years. No new output type is needed. According to The Quantum Insider's report, address formats and wallet software could largely stay as they are.

Anyone with two locks on the same door knows the logic. A burglar who can open the old lock still faces the new one. For the transition period, in which nobody knows for sure how fast quantum computers will mature, that is a cautious route. It avoids the hard cut of having to move all coins to new addresses in one go.

SPHINCS+ and Falcon: the quantum signature schemes on the table

Which post-quantum schemes enter the registry is to be settled in a separate discussion thread. In the forum, the author suggests starting with SPHINCS+ and its hybrid variant. SPHINCS+ is a hash-based signature scheme that the US standards agency NIST has codified as standard FIPS 205 under the name SLH-DSA. Its security depends only on the strength of hash functions, and it is stateless: a key can sign any number of times without the wallet having to keep count.

In the original post, mainnet_pat also mentions Falcon-512, a lattice-based scheme with considerably smaller signatures. Lattice schemes rest on hard problems in high-dimensional number lattices. ML-DSA, also a NIST standard, comes up in the discussion as well. One participant points to a demonstration by cryptographer Daniel J. Bernstein on key recovery and therefore urges caution.

Stateful schemes, in which each key may only produce a limited number of signatures, are explicitly to be kept out of the normal signature opcode. A counting error there could expose keys. Forum participant bitcoincashautist writes that only practically stateless schemes should be considered for extending the signature opcode.

Criticism in the developer forum: signature size and fees on Bitcoin Cash

The proposal is not uncontroversial, and the objections mainly concern size. According to the forum discussion, a SPHINCS+ signature is around 8 kilobytes. A Schnorr signature today needs 64 bytes, roughly a hundredth of that. The author does the maths himself in the forum: if all users switched to SPHINCS+, a block would grow to about 16 megabytes and fees would rise 80- to 160-fold. According to him, blocks today use only 100 to 200 kilobytes of the 32-megabyte limit.

Participant moonsettler therefore considers SPHINCS+ "Way overkill" for the transition period. The scheme is huge, complicated and not built for blockchains, he argues. He prefers flexible constructions based on Merkle trees and warns that many independent implementations could fragment the ecosystem. At the same time he concedes that a break of SPHINCS+ is unlikely. bitcoincashautist calls the scheme a bunker for the move, precisely because it is built so conservatively.

For holders, this debate matters more than it sounds. A quantum-resistant payment that costs many times the fees would mainly be used for larger amounts in long-term storage, less for the everyday payments Bitcoin Cash was once created for. Whether the proposal is considered mature by the cut-off date will be decided on exactly these points.

Quantum risk for Bitcoin and Bitcoin Cash: where the two networks stand

Bitcoin Cash shares its origins and the secp256k1 signature curve with Bitcoin. It therefore also shares the problem: addresses whose public key is already visible on the blockchain would be vulnerable to a sufficiently powerful quantum computer. How large that share is for Bitcoin and which Bitcoin addresses are already exposed today, we described in detail on September 5, 2026.

The difference lies in the pace of rule changes. For Bitcoin, proposals such as BIP-361 are on the table, but no activation date has been set. With its annual cycle, Bitcoin Cash has a mechanism that makes changes plannable, and with the Quantumroot vaults it already has a route on mainnet today. An accepted CHIP-2026-06 would be the next step, but not a finished solution: anyone wanting to protect their coins would still have to actively move them to a hybrid or quantum-resistant key.

Bitcoin Cash price this week: 19 percent below the previous week

BCH had a weak week. According to CoinGecko, the weekly high was around $289.51 and the low of the past 24 hours $225.23. On Thursday at around 1:50 a.m. CET, one Bitcoin Cash cost $229.48, 0.5 percent less than 24 hours earlier and around 19 percent less than seven days before. That leaves BCH more than 90 percent below its all-time high of $3,785.82 from December 2017.

There is no trigger specific to the decline. The market as a whole is under pressure: the Fear and Greed Index from alternative.me stood at 28 points on Thursday, in fear territory. On November 10, US inflation data for October came in above expectations, bitcoin briefly slipped to around $73,525, and markets have since been pricing in a rate hike by the US Federal Reserve in December. Altcoins with thinner order books usually lose more than bitcoin in such phases, and BCH is no exception.

BCH price levels: $289 above, $225 below

Three zones can be read from the weekly data for the coming days. These observations are no substitute for a forecast and are not a price target.

• On the downside, the first level is the daily low of $225.23. Below that lies the round $200 mark.
• On the upside, the zone around $250 is the next round level, which BCH has crossed from above in recent days.
• The weekly high at around $289.51 marks the level before the sell-off. Only above it would the week's decline be recovered.

A confirmed lock-in on November 15 would be technical news, not a guarantee for the price. Earlier upgrades did bring Bitcoin Cash attention. This autumn, however, the direction of the price has been set mainly by the broader market and by futures trading, which for BCH has also been running on the CME since October 2026.

Buying and storing Bitcoin Cash: MiCA exchanges and hardware wallets

If you want to buy BCH in the EU, first check whether the platform is authorised under the European crypto regulation MiCA. MiCA is the EU Markets in Crypto-Assets Regulation, which has applied to providers since the end of 2024 and requires a licence in an EU member state. Which providers list Bitcoin Cash and what buying there costs is shown in our crypto exchange comparison. How strictly individual exchanges are supervised is set out in the overview of regulated crypto exchanges.

For the quantum question, custody plays the bigger role. If the coins sit on an exchange, the exchange decides when and how it switches to new key schemes. If you hold them yourself, you keep control, but you then also have to make the move to a hybrid key yourself as soon as wallets offer it. A hardware wallet keeps the private keys offline. Our hardware wallet comparison gives an overview of suitable devices. Whether a particular device supports Bitcoin Cash is listed in the manufacturer's coin list.

If you trade BCH with leverage, for instance through futures or perpetuals, you also carry liquidation risk: if the price falls below a certain threshold, the exchange closes the position automatically and the capital you put in is lost.

Bitcoin Cash by November 15: the May date hinges on lock-in

By Sunday it will be clear whether Bitcoin Cash schedules the quantum proposal for the May 2027 upgrade or waits a year. The date changes little for the price at first, but for the long-term security of the coins it is an important step. Three points help put it in context:

1. Check your trading platform's licence. The comparison of regulated crypto exchanges shows where BCH can be traded under MiCA supervision.
2. Be clear about who holds your keys. For self-custody, the hardware wallet comparison helps you choose a device.
3. Record the purchase date and purchase price of every position. Tax rules depend on where you live, and a complete record makes any later calculation easier.

(As of November 12, 2026. This article is not investment advice. Prices and fee structures change; check the terms with the provider before you buy.)