Eaglesong Algorithm | cryptocurrencies, blockchains & live prices

Eaglesong is a novel cryptographic hash function designed from scratch by the Nervos Network team specifically for use in the Nervos Common Knowledge Base (CKB) blockchain. The algorithm employs a unique sponge construction with a 256-bit capacity and a 256-bit rate, processing input through a permutation function that operates on a 512-bit state. Eaglesong's permutation consists of 43 rounds, each applying a combination of bitwise operations including XOR, AND, and circular shifts, along with carefully chosen round constants. The design philosophy prioritized simplicity and analyzability, with the entire specification fitting on a single page.

Eaglesong was designed to provide 128-bit security against collision attacks and 256-bit security against preimage attacks, which is consistent with other modern hash functions producing 256-bit output. A key design goal was ASIC-friendliness rather than ASIC-resistance — the Nervos team intentionally created an algorithm that would be straightforward to implement in custom hardware, believing that ASIC mining ultimately leads to greater network security through dedicated investment. The simplicity of the bitwise operations makes Eaglesong efficient to implement in hardware while remaining fast enough for practical use on general-purpose CPUs. The algorithm underwent independent security analysis and was published as a peer-reviewed paper.

Eaglesong is used exclusively by Nervos CKB, a layer-1 blockchain that serves as the foundation of the Nervos Network's multi-layer architecture. Nervos CKB launched its mainnet in November 2019 with Eaglesong as its Proof of Work algorithm. The decision to create a custom hash function rather than using an existing one was driven by the desire to start with a clean mining landscape where no existing ASICs or optimized mining software could provide unfair early advantages. The Nervos team openly encouraged ASIC development for Eaglesong, and dedicated mining hardware eventually became available, contributing to the network's hash rate and security. This approach contrasts with many other projects that prioritize ASIC resistance.