cmz/CHANGELOG.md

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.4.1 - 2026-11-10

Fixes

• Update the version numbers and authors in the READMEs

0.4.0 - 2026-11-10

Added

• Derive the CMZ generator A automatically via a RFC 9380 hash-to-group of the generator. Applications no longer need to call cmz_group_init at startup.
• Add CMZGroup trait, cmz_generator_a function, and curve features for the automatic derivation. Ristretto support is enabled by default; P-256 and secp256k1 are available through the p256 and k256 features.

Changes

• Depend on sigma-compiler 0.3.0, rand 0.10, group 0.14, ff 0.14
• CMZ credential Point types must now implement group::prime::PrimeGroup, group::GroupEncoding, and hash2group::FromHash<hash2group::rfc9380::ExpandMsgXmd<sha2::Sha512>>. This combination of traits is now called CMZGroup.
• The rng parameter in various APIs generated by cmz changed from type &mut (impl CryptoRng + RngCore) to type &mut (impl CryptoRng + Rng) (due to the update to rand 0.10)

Fixes

• The ability to use cmz simultaneously for more than one group was broken before, and is now fixed.

0.3.0 - 2026-08-04

Changes

• Switch from bincode to postcard for serialization. The bincode crate is no longer maintained. Note that this causes a binary incompatibility with previous versions of the cmz crate. That is, previous versions and this one will not interoperate.

Fixes

• By default, when serializing a CMZCredential, skip the private key. That way, you don't accidentally send the private key if the issuer creates a credential completely on its own (not via a typical credential issuing protocol) and sends it to the client. Thanks to Morgan Hill from Radically Open Security.

Added

• Add serialize_with_privkey and deserialize_with_privkey if you explicitly do want to keep the private key when serializing a CMZCredential (for example, if the issuer is saving a credential to its own storage).

0.2.1 - 2026-03-26

Fixes

• Remembered to bump version number in README

0.2.0 - 2026-03-25

Added

• Add set_keypair function to CMZ credentials. This function sets both the private and public keys, without recomputing the public key from the private key. Using this function saves computation when you have both keys at hand.
• The new dump feature enables the corresponding dump feature of the sigma_compiler crate.

Changes

• Don't serialize an 8-byte length header in front of each Scalar and Point, which makes the generated proofs noticeably shorter.
• Depend on sigma-compiler version 0.2.0

Fixes

• Remove nondeterministic order of generated statements in the call to the sigma_compiler macro. We need the generated statements to be identical, not just equivalent (e.g., the same statements in a different order) because the order of the elements in the proof depends on the order of the statements.
• Don't use WnafBase multiplication at this time. It's both not constant time, and also in some cases slower than the regular multiplication (at least with Ristretto).

0.1.0 - 2025-10-10

Added

• Initial release