BTQ Testnet is Bitcoin Quantum’s Testnet. “Old BTC” What is Risk?

Takeaways

• Bitcoin’s risk is centered on the public key and signature security.

• BTQ’s Testnet explores the post-quantum environment in a Bitcoin similar setting.

• The post-quantum signatures increase the transactional size as well as block space requirements.

• “Old BTC risk” It focuses on the legacy output types, and addresses reuse patterns.

BTQ Technologies has announced the launch of a Bitcoin Quantum testing network on 12th January 2026. The testnet is a Bitcoin-like system designed for post-quantum digital signatures, without affecting Bitcoin’s mainnet governance.

The idea was that BTQ could replace Bitcoin’s current signature scheme MLDSA (the module-lattice standard) is a formalized version of the Federal Information Processing Standard (FIPS), 204. It can be used to verify post-quantum assumptions.

Remember that most Bitcoin quantum-threat modelsThe key condition is the public-key disclosure. In theory, if the public key of a key has already been exposed on chain, then a future quantum computing device with sufficient capabilities could attempt to find its private key.

Did You Know? BTQ Technologies is a firm that focuses on research in post-quantum encryption and blockchain security. The Bitcoin Quantum Testnet was created to examine how signatures that are quantum resistant behave within a Bitcoin like system.

Quantum changes: What are they?

The majority of Bitcoin quantum risk discussions are focused on digital signatures. They do not focus on Bitcoin coin supply, or on the notion that a quantum computing system could guess randomly generated wallets.

A cryptographically relevant quant computer (CRQC), which could be used to run a number of programs, is a specific issue. Shor’s algorithm The discrete-logarithm problem must be solved efficiently to generate a private secret from a publicly known key. Otherwise, the Elliptic Curve Digital Signature Algorithm and Schnorr’s based on signing are compromised.

Chaincode Labs frames This is the predominant quantum threat model of Bitcoin, because valid signatures could be used to enable unauthorized spending.

Risk can be divided into two categories: long-range and short-range. The former is where the public key has already been revealed onchain due to some scripts that are older or because they have been reused, while the latter occurs when public keys reveal themselves after a broadcast transaction and before confirmation. This creates a very narrow window of time.

There is no immediate threat to Bitcoin from a quantum-computer today, but mining impacts are a different and less constrained topic than the signature breaking.

Did You Know? Shor’s Algorithm is already a mathematical formula, but to be implemented, it needs a fault-tolerant, large quantum computer. These machines could allow private keys to be derived from public keys.

The BTQ project and its importance

BTQ’s Bitcoin Quantum testing network is essentially a Bitcoin Core based fork This replaces one of Bitcoins most fundamental primitives: signatures.

The word “In its” is a phrase that describes the situation. announcementBTQ stated that the testnet will replace ECDSA by ML-DSA. This is the NIST-standardized module-lattice digital signature standard FIPS 204.

The change requires a series of tradeoffs. MLDSA signatures can be up to 72 times bigger than ECDSA. To accommodate this, the testnet increases the block size to 64 Mebibytes.

It also uses the network to test its products and services throughout their entire lifecycle. wallet Creation, Transaction Signing and Verification, Mining, as well as basic infrastructure like a Block Explorer and mining pool.

Shortly, testnet has practical value in that it transforms post-quantum Bitcoin and turns it into an experimental performance.

Concentration of old BTC risks

The analysts talk What is the best way to get in touch with us? “old BTC risk” They usually refer to the public keys already visible onchain in a context of post-quantum.

In theory, a future CRQC that runs Shor’s algorithms could use these public keys to obtain the corresponding keys, and produce valid spending.

There are three output types immediately vulnerable to long-range attacks, specifically because they place elliptic-curve public keys directly in the locking script (ScriptPubKey): Pay-to-Public-Key (P2PK), Pay-to-Multi-Signature (P2MS) and Pay-to-Taproot (P2TR).

Distribution is not even:

• P2PK represents a small percentage of the unspent transactions outputs today (UTXOs). 0.025%It locks in a large portion of BTC’s value (about 8.68%, or 1,720.747 bitcoins).BTCMost of the coins are from Satoshi’s era.

• P2MS represents about 1.037 % of UTXOs. Reports estimate it to secure only 57 BTC.

• P2TRs are common, accounting for around 32.5% of the UTXOs. However, their value is small, at 0.74% (146,715 BTC) in that snapshot. This exposure is tied into TaprootThe key-path of, which shows a public key that has been tweaked on the chain.

You can reuse addresses to create new addressees. “spend-time” Once a key public appears, the chain remains visible.

BTQ claims that this large pool of potential affected users is a result of the exposed key framing. The company cites 6,26 million BTCs as being exposed. This is one of the reasons why it says that testing post-quantum signs in an environment similar to Bitcoin is worthwhile.

What is next for Bitcoin

Near-term, observability is the main focus.

The signature threat model, which we’ve explored in detail, is driven by the public-key leakage. It is for this reason that discussions are often centered on Bitcoin’s current wallet and scripting practice, which either expose public keys by default or reveal them early as in some older scripts.

“Old BTC risk” This is largely due to the historical types of outputs and reuse patterns, and it’s not something new. evenly to every coin.

Capacity is arguably the second and most practical constraint. It would be difficult to coordinate and blockspace even if there was social agreement on a post quantum migration.

River’s explainer This summary summarizes the academic estimates showing that timelines are sensitive to assumptions. Theoretically, if all transactions were migrations, timelines could be compressed dramatically. However, a more realistic allocation of blockspace can stretch a transition over years before taking into account governance or adoption.

BTQ’s Testnet is a good example of this. The testnet allows engineers to observe in an environment similar to Bitcoin the costs associated with post-quantum signing, such as larger data sizes, different limitations, and other factors, while not claiming Bitcoin’s imminent breakability.

Did You Know? Noise, or errors, is the biggest obstacle to quantum computing. Qubits are prone to errors, and fault-tolerant corrections must be implemented. The qubits are produced by using a large number of physical qubits. “logical” Before running long calculations needed to crack real-world encryption, qubits should be used.

Bitcoin mitigation: What it might look Like

On the protocol level quantum preparedness can be discussed as an ordered path.

BTQ has been experimenting with MLDSA and is revealing similar tradeoffs.

It is for this reason that some Bitcoin proposals first focus on reducing the structural vulnerability within existing script designs without immediately committing the blockchain to a post-quantum algorithm.

A recent example is Bitcoin Improvement Proposal (BIP) 360, which proposes a new output type called Pay-to-Tapscript-Hash (P2TSH). P2TSH has a similar structure to Taproot. However, it removes the key path spend (the route which relies on the elliptic curve signature), leaving behind a native tapscript route.

Similar ideas circulated On the Bitcoin Developer mailing list, under the wider “hash-only” The following are some examples of how to use “script-spend” Taproot family, often discussed as Pay-to-Quantum-Resistant-Hash (P2QRH)-style constructions. This proposal aims to reuse Taproot’s structure, but without the need for quantum-vulnerable/expensive keys.

It is important to note that nothing has been decided. Bitcoin’s response is a matter of debate, and if Bitcoin moves forward, it will be viewed as a coordination issue that must balance conservatism, compatibility, and cost.

The BTQ Testnet is very informative

BTQ’s Bitcoin Quantum testing network does not resolve the quantum debate but does highlight two important points.

Most credible threat models begin by focusing on public key locations, and this is the reason why “old coin” Patterns keep appearing during analyses.

The second problem is the coordination and engineering of post-quantum Bitcoin. BTQ Technologies own design decisions, like moving to MLDSA and raising block limits to allow for much larger signatures are examples of these trade-offs.

Testnets are a way to test costs and restrictions, but they should not be taken as proof of Bitcoin’s imminent breakability.