**StarkWare’s Vision: Using ZK STARKs and Bitcoin’s OP_CAT for Quantum-Safe Blockchains**
In a world increasingly concerned with quantum computing threats, blockchain technologists are racing to develop solutions that can keep decentralized networks secure. According to Eli Ben-Sasson, co-founder of StarkWare, the most effective way to address Bitcoin’s quantum vulnerabilities while simultaneously pushing for widespread adoption lies in the integration of ZK STARKs and possibly, Bitcoin’s historic OP_CAT opcode.
### The Quantum Threat to Bitcoin
The core security of Bitcoin currently relies on the Elliptic Curve Digital Signature Algorithm (ECDSA). However, ECDSA is vulnerable to Shor’s algorithm on a sufficiently powerful quantum computer. To counter this, the cryptographic community is developing Post-Quantum Cryptography (PQC) signature schemes. The primary challenge with these new schemes is their size; NIST-approved PQC signatures are 10 to 100 times larger than Bitcoin’s current Schnorr signatures.
This size increase presents a significant obstacle. If implemented naively, larger signatures could drastically reduce the network’s throughput, potentially limiting Bitcoin to fewer than 10 transactions per second. Furthermore, increasing the block size to accommodate these large signatures is a politically charged and technically complex solution that risks pushing network centralization, as it demands significantly more storage and computational power from node operators.
### The ZK STARKs Solution: Compression and Efficiency
Ben-Sasson proposes a two-pronged approach centered on Zero-Knowledge Succinct Non-Interactive Argument of Knowledge (ZK-SNARK) and Scalable Transparent Arguments of Knowledge (STARKs). Instead of adding massive signatures directly to the blockchain, the large Post-Quantum signatures would be aggregated off-chain. A single, small ZK STARK proof would then verify the entire block’s worth of transactions.
“The problem is ‘can everyone actually use Bitcoin?’” Ben-Sasson explained. “So for that you need massive scale. And for that, you need things like signature aggregation and just increasing the block size isn’t enough.”
This method offers a compelling advantage: efficiency. Verifying a ZK proof is computationally inexpensive and can even be done on lightweight devices like a Raspberry Pi. While generating the proof requires specialized hardware, the cost is estimated to be under $100,000 and is far less energy-intensive than Bitcoin mining.
### The Role of OP_CAT
For Bitcoin specifically, Ben-Sasson pointed to a seemingly simple solution that was originally designed by Satoshi Nakamoto: the OP_CAT opcode. OP_CAT was controversially removed from Bitcoin’s early codebase but reactivating it would be a relatively minor code change.
“\[He\] even introduced and then he removed it,” Ben-Sasson stated. “And if you add that, you can get things like STARK proofs and then aggregation and post-quantum security.”
He believes that enabling OP_CAT would “jump-start” Bitcoin’s evolution toward post-quantum security, providing a foundational tool for building more advanced cryptographic protocols like STARK aggregation.
### Industry Consensus and Next Steps
Ben-Sasson reported that prominent figures in the Bitcoin community, including Blockstream founder Adam Back and Core developer Luke Dashjr, have expressed support for the ZK STARK approach, even if they haven’t fully endorsed a specific implementation.
“Adam Back and Luke Dashjr don’t exactly see everything eye to eye, but on this I think they actually agree that it’s a great technology that, under the right terms, could find its way to Bitcoin,” he said.
While Ethereum has set a target of becoming post-quantum by 2029, Ben-Sasson suggests that Bitcoin’s journey will be more complex due to its governance model. Nevertheless, the potential for a faster, more secure, and more decentralized network through ZK aggregation and OP_CAT represents a significant opportunity for the future of bitcoin security.
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**Original Article Source:** [Cointelegraph – ZK STARKs are the best way to deal with the issues created with making Bitcoin quantum-safe — and to reach mass adoption at the same time — says StarkWare co-founder Eli Ben-Sasson](https://cointelegraph.com/news/starkware-zk-starks-bitcoin-quantum-safe-mass-adoption-el-ben-sasson)
