Privacy in Bitcoin is a condition that many bitcoiners long for and that many developers seek to improve without sacrificing the daily operation of the network. In this context, CriptoNoticias interviewed the developer Vano Chkheidze, based in Georgia, Europe, who designed UltrafastSecp256k1, a open source library which aims to optimize silent payments in Bitcoin, a mechanism that allows receive funds without exposing addresses on the blockchain.
The silent payments (BIP-352) offer the recipient of a transaction a unique and static address, without that address being visible on the network.
The counterpart is operational. Every time a new block arrives on the network, the user’s wallet has to analyze all the transactions it contains and make a cryptographic calculation on each one. This calculation is what allows us to detect if any of these transactions is a payment directed to the holder of the wallet. The work is intense, because a single block can have between 2,000 or 3,000 transactions.
On a powerful computer, that analysis is done quickly. In a phone, the work falls on the central processor, which is not designed for parallel operations.
According to what Chkheidze explained to CriptoNoticias, if the wallet remains offline for several hours and had to make up for the lost time, The analysis of the accumulated blocks could “take several minutes”.
That bottleneck, according to the developer, is what discourages users. “They close the application, change wallets or reuse addresses again,” he described, which leads to loss of privacy.
The library he built seeks to solve this problem by moving cryptographic operations from the central processor to a GPU (graphics processing unit), a component of equipment specialized in executing thousands of mathematical calculations in parallel.
In practice, this allows move that intensive work off the user’s devicetowards more powerful systems that scan transactions much more quickly. As a result, a process that could previously take minutes can be completed in seconds.
From “unviable” to functional on mobiles
The use of silent payments on mobile devices presents friction due to the need to process that information in the processor. The developer himself described it like this: “without a library like this, silent payments on a phone are technically possible, but practically painful”.
The problem appears when the wallet must update after being disconnected. In that scenario, he explained, the device has to process block by block and analyze thousands of transactions. “In a conventional wallet, this can take minutes. Users notice it: they close the application or reuse addresses,” he noted.
With the acceleration introduced by the library, that same process changes scale. “Catching up after being offline is measured in seconds, not minutes,” he said. In practical terms, he added, this makes silent payments “feel like a normal wallet.”
The goal of the project, he summarized, is straightforward: “to make the cryptography behind privacy in Bitcoin fast enough that users don’t bypass it.”
The role of the bookstore in silent Bitcoin payments
The library is not an isolated development. As Chkheidze himself explained, its implementation is already part of Frigatethe experimental server developed by Craig Raw for make silent payments viable in mobile walletsalso reported by CriptoNoticias.
Frigate is an Electrum server-type infrastructure that allows wallets to consult the network status without downloading the entire chain of blocks, and was presented as a solution to make silent payments practical on mobile devices.
That’s where the bookstore comes in. “UltrafastSecp256k1 is the engine underneath that scan,” the developer explained. Its function is to execute in parallel the cryptographic calculations that allow detecting if a transaction is directed to a user, something that In silent payments it must be made on each operation included in a block.
According to Chkheidze, this capability is what allows servers like Frigate to index blocks fast enough for wallets to consult the information in near real time.
Recognized limitations and results of the library
Finally, the author of the project points out two current limitations:
- The first has to do with security. The library has not been audited by third parties and its model is based on continuous internal testing and automated verification. Added to this is an additional difficulty pointed out by the developer himself: “GPU code is more difficult to review than CPU code,” which is why, he explained, the project invests “a lot in differential tests against libsecp256k1” to detect possible deviations.
- The second limitation is hardware support. Currently, the highest performance is achieved on NVIDIA GPUs using CUDA, while support for other platforms is still under development. “Parity with GPUs from AMD, Intel and Apple is still in progress,” he indicated, noting that this is one of the main open fronts of his work.
In parallel, the developer shared performance tests that illustrate the potential of the library under optimal conditions.
According to their measurements, ECDSA signature verification (the scheme used by Bitcoin) can reach about “70 million signatures per second on hardware.” NVIDIA RTX 4090while silent payments scanning can process an entire block of Bitcoin “in less than 100 milliseconds”. Even on CPU, he added, performance remains 2 to 5 times higher than equivalent standard implementations.
However, beyond these advances, silent payments still face the challenge of becoming a practical tool for the common user. The possibility that technologies like this reduce operational friction will be key for this privacy model to stop being a limited option and become more broadly integrated into the Bitcoin wallet ecosystem.