StarkWare launches quantum-secure Bitcoin transaction on mainnet

StarkWare mined a Bitcoin mainnet transaction that included a STARK-based, quantum-resistant attestation. The company built and broadcast the transaction from its test environment and the proof was included in a mainnet block as a live demonstration.

STARKs are zero-knowledge proofs that use collision-resistant hash functions and algebraic checks instead of number-theory problems. Bitcoin signatures today rely on elliptic-curve discrete logarithm problems, which in principle can be solved by large quantum computers using Shor’s algorithm. Embedding a STARK attestation in an on-chain transaction creates a record that a spend was authorized under a proof system that does not depend on those number-theory assumptions.

The transaction did not require a change to Bitcoin’s consensus rules. StarkWare put the proof material into parts of a standard transaction that the network accepts and showed miners would mine it. The demonstration was intended to collect measurements on data size, fee cost and script compatibility.

StarkWare pointed out trade-offs in the implementation. STARK proofs are larger than conventional signatures, which increases transaction data and fees when published on-chain. The company outlined approaches to reduce on-chain footprint, including off-chain aggregation, compression techniques and using layer-two channels.

Participants in the Bitcoin community have discussed several options to protect funds from future quantum threats, including rotating legacy keys, hybrid signatures that combine classical and post-quantum algorithms, and protocol upgrades to support new signature schemes. StarkWare’s experiment adds a practical example of recording a post-quantum attestation on mainnet without immediate protocol changes while highlighting engineering constraints.

StarkWare described the work as research and engineering aimed at testing feasibility and gathering real-world data on how proofs behave when broadcast, mined and stored by the network. The company plans to continue work on reducing proof sizes and improving packing strategies to lower on-chain costs and make quantum-resistant proofs more practical for routine use.