Key Highlights
- Avihu Levy, StarkWare’s Chief Product Officer and co-author of BIP-360, released Quantum Safe Bitcoin (QSB) on April 9, with a hash-based scheme that makes transactions resistant to Shor’s algorithm today, using only Bitcoin’s existing Script limits (201 opcodes, 10,000 bytes).
- Weeks after Google’s March research raised alarms that quantum computers could crack exposed public keys far faster than expected while two independent teams delivered working prototypes within 48 hours.
- QSB offers immediate quantum resistance via “hash-to-sig” puzzles but comes with steep costs—roughly $75–$200 per transaction due to larger sizes and heavy GPU compute. Developers position it as a last-resort option for high-value holdings, not everyday use, while longer-term upgrades like BIP-360 continue in parallel.
In a latest attempt to save Bitcoin from quantum threat, Avihu Levy, Chief Product Officer at StarkWare and co-author of the recently merged BIP-360 quantum-resistant address proposal, published a research paper and open-source code for Quantum Safe Bitcoin (QSB).
The arrangement—shared on Github library—lets users create transactions that resist attacks from future quantum computers while staying fully compatible with Bitcoin’s existing Script rules—no soft fork, no upgrade, no network coordination required.
Instead of relying on elliptic curve signatures that Shor’s algorithm could eventually break, QSB uses hash-based “hash-to-sig” puzzles. These depend on the preimage resistance of cryptographic hashes, which are widely believed to remain secure even against large-scale quantum machines.
Levy’s implementation fits inside Bitcoin’s strict legacy limits of 201 opcodes and 10,000 bytes, and the code is already available on GitHub for anyone to test.
StarkWare CEO Eli Ben-Sasson called the development “huge,” saying it effectively makes Bitcoin quantum-safe immediately for those willing to use it. The move comes from a team long focused on zero-knowledge tech and post-quantum cryptography, including their work on STARK proofs and recent integration of quantum-resistant elements into Starknet.
From crisis warnings to rapid solutions
Only weeks earlier, the mood around Bitcoin’s quantum risk had turned grim. In late March, Google researchers published findings suggesting a cryptographically relevant quantum computer might need far fewer resources than previously estimated—potentially cracking exposed public keys in minutes rather than hours.
With millions of BTC in addresses where public keys are already visible on-chain, analysts warned of a serious long-term threat. Some called the problem nearly unsolvable without painful network changes or the risk of stranding legitimate funds.
Developer forums buzzed with concern over how to protect old wallets, including dormant ones possibly tied to Satoshi. The narrative was clear: Bitcoin’s core cryptography faced a structural weakness that could prove difficult to patch in a decentralized system.
Then the responses arrived in quick succession. On April 8, Lightning Labs CTO Olaoluwa “Roasbeef” Osuntokun released a working prototype using zk-STARK proofs. It allows users to prove ownership of BIP-86 Taproot wallets from their seed phrase without exposing private keys—essentially an escape hatch for funds that might otherwise be frozen during a future emergency quantum-defense upgrade.
Now just a day later, StarkWare’s QSB provided a different angle using proactive quantum-resistant transactions that anyone can use right now.
Costs, limits, and the road ahead
To note, neither solution is perfect for daily use. QSB transactions are expensive, with estimates ranging from $75 to $200 each due to larger sizes and intensive GPU computation needed for proof generation. Developers position it as an emergency or “last-resort” tool for high-value, long-term holdings rather than routine payments.
The Lightning Labs prototype similarly targets a specific rescue scenario. Both highlight the creativity possible within Bitcoin’s constraints, relying on hashes, zero-knowledge techniques, and clever scripting.
The speed of these releases—two functional approaches within 48 hours—has shifted the conversation. What felt like a slow-burning, potentially intractable governance challenge now looks more manageable through layered, opt-in innovations.
Longer-term efforts continue, including BIP-360 for new quantum-resistant addresses via soft fork, along with ideas like reduced address reuse and Pay-to-Merkle-Root schemes.
No one suggests quantum computers capable of breaking Bitcoin exist today, but preparation has clearly accelerated.
For Bitcoin holders, the takeaway is reassuring. A major player like StarkWare just proved the network can adapt quickly and creatively when real threats appear on the horizon. QSB may not replace everyday transactions anytime soon, but it buys critical time and demonstrates that decentralized development can still deliver fast, practical defenses.
Also read: Coinbase CEO Backs CLARITY Act After Blocking it Twice in 2026
