Ethereum Ditches Poseidon for SHA and BLAKE in Quantum Security Pivot

The Ethereum Foundation has made a significant shift in its strategy for quantum resistance. After years of pursuing Poseidon as the backbone of its Layer 1 (L1) cryptography, the foundation will now adopt established hash functions such as SHA and BLAKE.

This decision marks a milestone in Ethereum's ongoing quest to stay ahead of the threat posed by quantum computers. The foundation had been developing Poseidon for over eight years, designed to be friendly to zero-knowledge proof systems, or SNARKs. However, recent advances in cryptographic research have made traditional hashes like SHA and BLAKE efficient enough to use inside SNARKs.

The Ethereum Foundation's Justin Drake announced the pivot on X (formerly Twitter), stating that the new approach flips the old paradigm on its head: rather than designing new hashes for SNARKs, Ethereum is now adapting SNARKs to work efficiently with proven, existing hashes. This gives Ethereum the benefit of decades of cryptanalysis, making its cryptography easier to maintain and upgrade in the long term.