Update changelog

CHANGELOG.md

@@ -10,6 +10,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `k256` dependency bumped to 0.10 (and to match it, `chacha20poly1305` to 0.9, `elliptic-curve` to 0.11, `ecdsa` to 0.13, `signature` to 1.4, MSRV to 1.56, and Rust edition to 2021). ([#87])
 - ABI changed because of the internal change in hashing to scalars (we can hash to non-zero scalars now). Correspondingly, `OpenReencryptedError::ZeroHash` and `SecretKeyFactoryError` have been removed, and `SecretKeyFactory::make_key()` was made infallible. ([#87])
+- Internal cloning in the library methods was eliminated, and, as a result, several methods now consume the given objects. Namely: `Signer::new()` consumes the given `SecretKey`,
+`KeyFrag::verify()` and `CapsuleFrag::verify()` consume the given kfrag/cfrag, `reencrypt()` consumes the cfrag (but not the capsule). ([#91])
+- As a consequence, `KeyFrag::verify()` and `CapsuleFrag::verify()` return the original frag on error (as a tuple with the error itself), for logging purposes (since the original object is not available anymore). ([#91])
+- `VerifiedKeyFrag::to_unverified()` and `VerifiedCapsuleFrag::to_unverified()` were renamed to `unverify()` and consume the corresponding frag. ([#91])
 
 
 ### Fixed
@@ -18,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 [#87]: https://github.com/nucypher/rust-umbral/pull/87
+[#91]: https://github.com/nucypher/rust-umbral/pull/91
 
 
 ## [0.4.0] - 2021-12-24