Second-layer Bitcoin development has produced tangible results. Lightning and Liquid, the two main approaches to processing transactions off-chain, have both shown meaningful progress in recent months
Second-layer Bitcoin development has produced tangible results. Lightning and Liquid, the two main approaches to processing transactions off-chain, have both shown meaningful progress in recent months. But the focus has now shifted to the core protocol itself. Pieter Wuille, a Bitcoin developer with significant influence on the codebase, filed a draft Bitcoin Improvement Proposal proposing a fundamental switch in how the network validates transactions cryptographically. The change involves moving from the elliptic curve digital signature algorithm to Schnorr signatures.
Wuille submitted the draft last month. This marks the first practical effort toward adoption after Schnorr has circulated in Bitcoin's development discussions for years.
Segregated witness made this possible. The upgrade, deployed last year, introduced script versioning, a feature that allows Bitcoin to deploy new cryptographic capabilities through a soft-fork. Nodes running older software can stay compatible without upgrading, avoiding the network splits that hard-forks produce.
A patent problem shaped Bitcoin's original design. Satoshi Nakamoto selected ECDSA, the elliptic curve digital signature algorithm, as Bitcoin's signing mechanism. Claus P. Schnorr had developed an alternative signature scheme decades prior. But U.S. Patent 4,995,082 protected Schnorr's invention until late 2008. That patent monopoly meant ECDSA became the standard cryptographic scheme across the computing industry. Schnorr never achieved the same library support or institutional backing that ECDSA accumulated. By the time the patent expired, Bitcoin was established and switching seemed impractical and risky.
Wuille's specification details 64-byte Schnorr signatures using secp256k1, Bitcoin's existing elliptic curve. Current ECDSA signatures measure 71 to 75 bytes. The difference seems modest—four to eleven bytes per transaction. But Bitcoin processes roughly 200,000 transactions every day. Reduce signature size and the blockchain grows less dense with redundant data. The savings compound over time, affecting both storage requirements and bandwidth needs.
Multi-signature transactions capture the most dramatic benefit. These arrangements require multiple parties to approve a transfer. Exchanges, custodians, and institutional wallets employ them as a security measure. Right now, every signature must appear in the transaction. A wallet using five-of-seven signatures includes all seven signatures in the transaction data. Schnorr lets signatures merge into a single 64-byte proof. A five-of-seven setup and a standard transfer both occupy the same space. That transforms the cost structure. Institutions using multi-signature security gain the same efficiency as ordinary users, without the historical penalty.
Batch validation provides another computational advantage. Bitcoin nodes can verify many Schnorr signatures as a batch, using fewer computational cycles than sequential verification. This matters for full nodes processing blocks and for any participant validating chains.
The proposal extends to applications beyond basic transactions. Adaptor signatures could enable new atomic swap designs, letting users exchange assets across different blockchains without intermediaries. Scriptless scripts allow developers to build transaction conditions without Bitcoin's Script language. They manipulate the underlying mathematics of Schnorr signatures instead.
Implementation is technically straightforward. Wuille constructed a clear technical specification. The actual hurdle is political consensus. Bitcoin operates without central authority. Major changes require miners, node operators, developers, and exchanges to coordinate and agree. Different groups have different priorities and risk appetites. Wuille acknowledged that technical work presents no serious obstacle. Securing agreement across the Bitcoin community could prove difficult, as the development culture tends toward caution on protocol changes.
The urgency of this change rises when block space becomes scarce. Bitcoin produces blocks every ten minutes with a one-megabyte limit. When transaction volume swells, users compete by paying higher fees to get included. Congestion can last for months. Schnorr signatures—smaller and compressible multi-sigs—address this core bottleneck. Once fees climb and users feel the squeeze, the efficiency case becomes undeniable.
This proposal marks the beginning. Adoption requires further specification work, testing across the network, miner signaling, and activation parameters. Months will pass before transactions flowing through Bitcoin improve. But discussion has shifted from theoretical to actionable.
