StarkWare Achieves Quantum-Safe Bitcoin Transaction on Mainnet

StarkWare has made a significant advancement in securing Bitcoin against quantum computing threats by executing the first quantum-safe transaction on the mainnet. This milestone was achieved by Avihu Levy, StarkWare’s General Manager of Applications, who confirmed the transaction in block 964,199 on August 26, 2026, utilizing a method that replaces traditional elliptic-curve cryptography with hash-based constructions.

The transaction involved a modest amount of 10,000 satoshis and incurred a fee of 5,179 satoshis. The core innovation lies in the use of hash preimage resistance, which is believed to withstand quantum attacks, providing approximately 118-bit second-preimage resistance under a quantum threat model.

Levy's implementation, published as open-source in April 2026, operates within Bitcoin’s existing script and opcode structures, allowing for the mining of non-standard transactions while adhering to consensus rules. StarkWare CEO Eli Ben-Sasson emphasized that this achievement enables Bitcoin holders to secure their assets in a quantum-resistant manner, paving the way for future enhancements.

However, the quantum-safe method requires off-chain GPU computation, with costs estimated between $75 and $150 per transaction. While this may seem high for small transactions, it becomes more justifiable for securing larger amounts of Bitcoin. It’s important to note that only funds specifically transferred into the quantum-safe format are protected, leaving approximately 7 million BTC vulnerable due to publicly visible keys.

StarkWare’s broader strategy includes a three-phase post-quantum roadmap for its Layer 2 network, Starknet, with the quantum-safe Bitcoin approach serving as a temporary solution until a more comprehensive soft-fork can be developed.