Introducing CIRCL: An Advanced Cryptographic Library

Cloudflare has released a cryptographic library called CIRCL during its Crypto Week 2019. The Go-based library includes packages that target cryptographic algorithms for post-quantum (PQ), elliptic curve cryptography, and hash functions for prime groups. It is designed to be useful for a broad audience and aims to provide a complementary set of implementations that are more aggressively optimized or less commonly used but have a good chance at being very useful in the future. The CIRCL library includes packages for post-quantum cryptography, key exchange, digital signatures, hashing to elliptic curve groups, and bilinear pairings. It also contains an implementation of Supersingular Isogeny-based Diffie-Hellman (SIDH) and CCA2-secure Supersingular Isogeny-based Key Encapsulation (SIKE). The development of CIRCL follows best practices on the secure development, including writing constant-time code to prevent timing based attacks.