Introducing CIRCL: An Advanced Cryptographic Library

This post introduces CIRCL, a new Go-based cryptographic library developed by Cloudflare. CIRCL includes implementations for post-quantum cryptography (SIKE, SIDH), key exchange (X25519, X448, FourQ), digital signatures (Ed25519), and hash functions for prime groups. It also features optimized ECC curves like P-384. The library is designed to be complementary to existing Go crypto packages, offering more aggressively optimized or less commonly used algorithms. The post provides code examples for using SIKE for key encapsulation and discusses the trade-offs between field sizes and performance.