Dr. Pieter Wuille: Current Bitcoin Protocol Is 'Not Quantum Secure'

William Casarin, a Haskell and Rush computer programmer, has suggested not using taproot (or at least carefully considering the implications), a recently published Bitcoin Improvement Proposal (BIP) that aims to enhance the leading cryptocurrency’s privacy and overall network efficiency.

Casarin, a Vancouver-based game developer, pointed out via Twitter that taproot is “pay to pubkey, not pubkey hash.” He also questioned why the Bitcoin (BTC) protocol developers would integrate the “complicated script validation logic” associated with BIP-Taproot as the cryptocurrency’s codebase “might be insecure in 30 years” from now.

In response to Casarin’s comments, Mario Gibney, the Customer Support Team Lead at Blockstream, said that he was surprised as he had not heard about it before. Casarin also asked:

Is it possible to have a pay to pubkey hash version of taproot?

According to prominent Bitcoin Core developer Dr. Pieter Wuille, hashing public keys “doesn't add any security.” Wuille, co-founder at Blockstream, added that “the widely repeated claim that it protects against quantum computers is nonsense.” He also clarified that “anyone who ever reused an address, or shared an xpub (or used Electrum) has their pubkeys already public.”

“Bitcoin Outputs Aren’t Secure Against a Quantum Computer Even When They’re Hashed”

Responding to Wuille’s statements, Casarin noted that there are “theoretical proposed algorithms for quantum attacks on pubkeys, but not hashes.” The physics enthusiast then questioned Wuille’s claim regarding hashing public keys not being able to enhance security.

He acknowledged that pay to script hash (p2sh) may have “reduced” security “due to collisions”, however he asked Wuille to point out the the main arguments that suggest “pubkey attacks impossible.”

Wuille remarked:

Taproot, a “Neat Idea”

Casarin then argued that you could “buy yourself some in the inflight case.” He also mentioned that if he we was operating a QC, then he’d focus on “the already exposed outputs.” Casarin further noted:

I can't imagine ever using taproot for that reason. Pretty neat idea otherwise.

In response, Wuille stated:

If there's ever evidence of theft due to a QC, and 5M BTC are readily available for the taking to such a hypothetical machine, do you think BTC will still have any value left?

According to Casarin, the only way Bitcoin would manage to survive is if users were aware of the fact that they can “at least move to quantum secure outputs.”

Current State of QCs: IBM Has 50 Qubits, Google 72

Meanwhile, Wuille mentioned: 

Any unconfirmed transaction in flight exposes public keys, so if a QC exists, at least moving coins around safely becomes impossible. Further, a massive fraction of the currency supply can be taken. Lastly, you likely have exposed your own pubkey already.

He added:

Given all those hypothetical attack models that pubkey hashing doesn't help with at all, I think it's fair to say that Bitcoin as it exists today is not quantum secure, period.

Confirming that QCs exist today and elaborating on their current state of development, Twitter user Noclone3 pointed out “QCs do already exist in a primitive form, namely, not error corrected. IBM has 50 qubits, Google 72, Rigetti should deliver 128, IonQ 160. The burden of error correction depends on the number of needed operations (gates) and should be of the order of 1000 qubits x logical qubit.”

Crypto Market Update: Focus on BTC, ETH, BCH, BNB, XMR, and DASH

Siamak Masnavi

This article provides a quick overview of how the crypto markets have been doing—with the focus on Bitcoin (BTC), Ether (ETH), Bitcoin Cash (BCH), Binance Coin (BNB), Monero (XMR), and Dash (DASH)—over the past 24-hour period.

Overall, September 17th is proving to be a bit of a mixed day, with 12 of the top 20 cryptocurrencies (by market cap) in the red at press time (around 06:25 UTC).


BTC-USD 24 Hour Chart - 17 Sep 2019.png

The bad news is that are still waiting for the launch of Bakkt's physically-delivered daily and monthly Bitcoin futures contracts. So, Bitcoin is still trading mostly sideways, hovering around the $10,300 mark. The good news is that the launch is expected to take place in less than one week (i.e. on September 23), as was confirmed by this tweet that Bakkt sent out on September 16:


ETH-USD 24 Hour Chart - 17 Sep 2019.png

The Ether (ETH) price continues its upward movement toward the $200 mark, up another 2.24% in the past 24-hour period (making it up 4.32% in the past 7-day period). What may have helped the Bitcoin price yesterday (September 16) is the announcement by crypto payment processor BitPay that in the near future it will be possible for its customers to accept Ether payments for purchases of goods and services. Also, the BitPay wallet will support Ether.

Ethereum co-founder Vitalik Buterin had this to say about the news:

"It is exciting to see BitPay leading the way in integrating Ethereum into global payment systems. This truly opens up a new world of possibilities for the Ethereum ecosystem, and together we can continue to be a leading innovator for real world use cases for cryptocurrencies.


BCH-USD 24 Hour Chart - 17 Sep 2019.png

On Monday (September 16), Bitcoin.com announced that it had entered into a strategic partnership with Taiwanese smartphone manufacturer HTC, as a result of which the Bitcoin.com wallet will come preinstalled on HTC's current and upcoming blockchain phones (Exodus 1 and Exodus 1s):


BNB-USD 24 Hour Chart - 17 Sep 2019.png

Although BNB is currently in the red, this may change during the next several hours once all of the six mini announcements that Binance plans to make today have come out:

The first of the six announcements that Binance CEO Changpeng Zhao (aka "CZ") referred to is the addition of support for Cosmos (ATOM) to Binance's Margin Trading platform:


XMR-USD 24 Hour Chart - 17 Sep 2019.png

OKEx Korea announced on Monday (September 16) that it intends to delist all five privacy coins it is currently supporting, i.e. XMR, DASH, ZEC, ZEN, and SBTC, due to concerns that these cryptocurrencies do not allow it to implement FATF's so-called "travel rule". 10 October 2019 is the date on which transaction (i.e. trading) support ends.


DASH-USD 24 Hour Chart - 17 Sep 2019.png

Since OKEx Korea's delisting announcement mentioned DASH, you would expect it to be down today, just like XMR. However, it is not, and that is very likely due to the fact that today (September 17) is the day that trading in DASH is expected to start on Coinbase Pro on/after 09:00 PST (16:00 UTC) provided that there is sufficient liquidity.

Featured Image Court: Photo via Pixabay.com