StarkWare Confirms Quantum Safe Bitcoin Transaction on Mainnet

StarkWare has confirmed that it successfully executed a Bitcoin transaction on mainnet using its Quantum Safe Bitcoin (QSB) design, which is claimed to be resistant to quantum attacks. The transaction, identified as 305a24ff…ab07, was mined in block 964,199 on August 26 and combined two inputs with outputs of 39,179- and 10,000-satoshi, creating a single output of 44,000 satoshis.

The QSB design uses Bitcoin's existing legacy scripting rules, avoiding the need for a soft fork. The method relies on RIPEMD-160 preimage resistance rather than elliptic curve hardness to achieve its claimed security properties. According to Avihu Levy, the researcher who implemented the design, it is only used as a vehicle and not as part of the verification path.

The transaction was labeled 'Non-Standard' by Mempool.space due to its non-standard nature, requiring a direct path to a miner. StarkWare attributed this to MARA's Slipstream service providing the mining path. Levy described QSB as a last-resort measure, citing that it does not scale well for large users and throughput.

The onchain record confirms the transaction was included in a block, but it does not independently establish the construction's claimed resistance to quantum attacks. StarkWare emphasized that QSB protects coins only after they are moved into a special output and does not retrofit resistance onto ordinary ECDSA- or Schnorr-secured holdings.