CIRCL (Cloudflare Interoperable, Reusable Cryptographic Library) is a collection of cryptographic primitives written in Go. The goal of this library is to be used as a tool for experimental deployment of cryptographic algorithms targeting Post-Quantum (PQ) and Elliptic Curve Cryptography (ECC).

🚨 This library is offered as-is, and without a guarantee. Therefore, it is expected that changes in the code, repository, and API occur in the future. We recommend to take caution before using this library in a production application since part of its content is experimental. All security issues must be reported, please notify us immediately following the instructions given in our Security Policy.

You can get CIRCL by fetching:

go get -u github.com/cloudflare/circl

• X25519
• X448
• Curve4Q

• Ed25519
• Ed448

• P-256, P-384, P-521, FIPS 186-4
• Ristretto
• Hash to Curve

• HPKE: Hybrid Public-Key Encryption
• VOPRF: Verifiable Oblivious Pseudorandom function: OPRF, VOPRF and POPRF modes.
• BlindRSA: Blind RSA signatures.
• CPABE: Ciphertext-policy Attribute-based Encryption.

• CSIDH: Post-Quantum Commutative Group Action
• Kyber KEM: modes 512, 768, 1024
• FrodoKEM KEM: modes 640-SHAKE
• (insecure, deprecated) SIDH/SIKE: Supersingular Key Encapsulation with primes p434, p503, p751

• Kyber PKE: modes 512, 768, 1024

• Dilithium: modes 2, 3, 5

• Fp25519, Fp448, Fp381

• P-384 Curve
• FourQ
• Goldilocks
• BLS12-381: Bilinear pairings, hash to G1 and G2.

• Keccak f1600 Permutation

• FIPS 202: SHAKE128 and SHAKE256
• BLAKE2X: BLAKE2XB and BLAKE2XS
• KangarooTwelve: KangarooTwelve

• Schnorr: Prove knowledge of the Discrete Logarithm.
• DLEQ: Prove knowledge of the Discrete Logarithm Equality.

Library comes with number of make targets which can be used for testing and benchmarking:

• test performs testing of the binary.
• bench runs benchmarks.
• cover produces coverage.
• lint runs set of linters on the code base.

To contribute, fork this repository and make your changes, and then make a Pull Request. A Pull Request requires approval of the admin team and a successful CI build.

To cite CIRCL, use one of the following formats and update the version and date you accessed this project.

APA Style

Faz-Hernández, A. and Kwiatkowski, K. (2019). Introducing CIRCL:
An Advanced Cryptographic Library. Cloudflare. Available at
https://github.com/cloudflare/circl. v1.3.3 Accessed May, 2023.

Bibtex Source

@manual{circl,
  title        = {Introducing CIRCL: An Advanced Cryptographic Library},
  author       = {Armando Faz-Hern\'{a}ndez and Kris Kwiatkowski},
  organization = {Cloudflare},
  abstract     = {{CIRCL (Cloudflare Interoperable, Reusable Cryptographic Library) is
                   a collection of cryptographic primitives written in Go. The goal
                   of this library is to be used as a tool for experimental
                   deployment of cryptographic algorithms targeting Post-Quantum (PQ)
                   and Elliptic Curve Cryptography (ECC).}},
  note         = {Available at \url{https://github.com/cloudflare/circl}. v1.3.3 Accessed May, 2023},
  month        = jun,
  year         = {2019}
}

CFF Style

See attached CITATION.cff file.

The project is licensed under the BSD-3-Clause License.