Undocumented API incompatibility in EC: renamed keyword argument in `EllipticCurvePrivateKey.exchange()`

[MatthiasValvekens]

Hi, I have the following snippet breaking on the latest version of cryptography (42.0.1):

        if isinstance(priv_key, EllipticCurvePrivateKey):
            ecdh_value = priv_key.exchange(
                ECDH(), peer_public_key=originator_pub_key
            )

Removing the usage of kwargs fixes it. Reproducible on Python 3.11, but probably the same issue exists everywhere (I can rerun my CI in fail-late mode if needed). From what I can tell, the breaking change was introduced here, in the initial migration of this code to Rust: f38eb4a#diff-868a141c8ba335a462dc768991ee88d95cad873c531d64b10a88385beac311b2R311, renaming peer_public_key to public_key. I see in the release notes for 42.0.1 that the sign function required a similar fix, so I suspect this was overlooked for similar reasons.

EDIT for completeness: the error raised is this one, on the call to exchange:

   TypeError: ECPrivateKey.exchange() got an unexpected keyword argument 'peer_public_key'

Thanks!

[alex]

Thanks for the report. I think we'll try to get a fix in and then a backport quickly -- we'll be doing a releaes tomorrow.

[MatthiasValvekens]

Thanks for the lightning-fast fix! :)