Adam Back Challenges BIP-361 Proposal at Paris Blockchain Week

The ongoing debate over Bitcoin's quantum resistance could redefine security protocols and impact the value of your holdings.

• Adam Back opposed the BIP-361 proposal at Paris Blockchain Week, advocating for optional upgrades instead of enforced coin freezes.
• BIP-361, drafted by Jameson Lopp and co-authors, suggests a phased approach to freeze unmigrated coins to protect against quantum threats.
• 1.7 million BTC in legacy addresses, including Satoshi Nakamoto's holdings, are at risk of theft due to vulnerabilities in current cryptographic methods.

• Quantum computing poses a significant threat to Bitcoin's elliptic curve cryptography, potentially allowing hackers to derive private keys from public keys.
• 1.7 million BTC, valued at approximately $70-80 billion, are in legacy formats vulnerable to quantum attacks, raising concerns about their security.
• Historical precedents in Bitcoin's development, like the voluntary soft fork for Taproot, emphasize user choice and consensus over coercive measures.

The debate surrounding Bitcoin's quantum resistance has intensified with the introduction of BIP-361, a proposal that aims to address the potential vulnerabilities posed by quantum computing. This proposal, published on April 15, 2026, outlines a three-phase soft fork strategy. The first phase, set to activate three years post-approval, would prohibit new payments to legacy addresses. The second phase, five years later, would invalidate old signatures, effectively freezing unmigrated coins to prevent what proponents term "intergenerational theft." This approach has sparked significant controversy within the Bitcoin community.

Adam Back, CEO of Blockstream, has emerged as a prominent critic of BIP-361. At the same event where the proposal was introduced, he advocated for optional quantum-resistant upgrades rather than enforced measures. Back argues that the focus should be on education and incentivizing users to migrate to more secure systems voluntarily. He points to the rapid resolution of past bugs in Bitcoin's code as evidence that the community can adapt without resorting to coercive tactics. Back's stance is rooted in a belief that the current quantum threat is still largely theoretical, with quantum computing capabilities remaining in the experimental stage.

The implications of this debate extend beyond technical specifications; they touch on fundamental principles of Bitcoin's decentralized ethos. Supporters of BIP-361 argue that the integrity of Bitcoin's fixed supply must be protected against potential quantum adversaries. In contrast, critics like Back view the proposal as a form of expropriation that undermines the very decentralization that Bitcoin was designed to uphold. This schism within the community has led to polarized opinions, with media coverage amplifying the divide.

As the debate continues, the Bitcoin community remains engaged in discussions across various platforms, including social media and forums. Despite the controversy, there has been no significant volatility in Bitcoin's price or governmental interventions, indicating that the market is currently absorbing the implications of these proposals without immediate panic.

• Bitcoin holders: Those with assets in legacy addresses are directly impacted by the potential for theft and the implications of the BIP-361 proposal.
• Developers and miners: Changes in protocol could affect their operations and the overall security of the network.
• Investors and institutions: Entities holding significant Bitcoin investments must consider the long-term viability of their assets in light of quantum threats.

• Community consensus: Monitor discussions within the Bitcoin community regarding BIP-361 and alternative proposals, as this will shape future protocol decisions.
• Quantum computing advancements: Keep an eye on developments in quantum technology, as breakthroughs could accelerate the urgency of implementing quantum-resistant measures.
• Market reactions: Watch for any shifts in Bitcoin's price or trading volume in response to ongoing debates and proposals, which could indicate investor sentiment.