Ecdsa

New API:
* `to_ssh` in `VerifyingKey` and `SigningKey`, supports Ed25519 keys only
(Pablo Mazzini)

New features:
* Support for twisted Brainpool curves

Doc fix:
* Fix curve equation in glossary
* Documentation for signature encoding and signature decoding functions

Maintenance:
* Dropped official support for 3.3 and 3.4 (because of problems running them
in CI, not because it's actually incompatible; support for 2.6 and 2.7 is
unaffected)
* Fixes aroung hypothesis parameters
* Officially support Python 3.11 and 3.12
* Small updates to test suite to make it work with 3.11 and 3.12 and new
releases of test dependencies
* Dropped the internal `_rwlock` module as it's unused
* Added mutation testing to CI, lots of speed-ups to the test suite
to make it happen
* Removal of unnecessary `six.b` literals (Alexandre Detiste)

Deprecations:
* `int_to_string`, `string_to_int`, and `digest_integer` from `ecdsa.ecdsa`
module are now considered deprecated, they will be removed in a future
release

New API:
* `curve_by_name` in `curves` module to get a `Curve` object by providing curve
name.

Bug fix:
* Make the `VerifyingKey` encoded with explicit parameters use the same
kind of point encoding for public key and curve generator.
* Better handling of malformed curve parameters (as in CVE-2022-0778);
make python-ecdsa raise `MalformedPointError` instead of `AssertionError`.

Doc fix:
* Publish the documentation on https://ecdsa.readthedocs.io/,
include explanation of basics of handling of ECC data formats and how to use
the library for elliptic curve arithmetic.
* Make object names more consistent, make them into hyperlinks on the
readthedocs documentation.
* Make security note more explicit (Ian Rodney)
* Fix the `explicit` vs `named_curve` confusion in `VerifyingKey` docs.

Maintenance:
* Updated black version; slight changes to formatting
* Include interoperability tests for Ed25519 and Ed448 with OpenSSL.

New features:
* Support for point precomputation for EdDSA.

Maintenance:
* Fix few typos (thanks to Tim Gates and Kian Meng Ang).

Bug fix:
* Accept private EdDSA keys that include public key in the ASN.1 structure.
* Fix incompatibility with Python 3.3 in handling of memoryviews of empty
strings.

New features:
* Support for EdDSA (Ed25519, Ed448) signature creation and verification.
* Support for Ed25519 and Ed448 in PKCS8 and public key files.

New API:
* CurveEdTw class to represent the Twisted Edwards curve parameters.
* PointEdwards class to represent points on Twisted Edwards curve and
provide point arithmetic on it.

New API:
* Keys that use explicit curve parameters can now be read and written.
Reading of explicit curves can be disabled by using the
`valid_curve_encodings` keyword argument in `VerifyingKey.from_pem()`,
`VerifyingKey.from_der()`, `SigningKey.from_pem()`, and
`SigningKey.from_der()`.
* Keys can now be written with use of explicit curve parameters,
use `curve_parameters_encoding` keyword argument of `VerifyingKey.to_pem()`,
`VerifyingKey.to_der()`, `SigningKey.to_pem(), or `SigningKey.to_der()` to
specify the format. By default `named_curve` will be used, unless the
curve doesn't have an associated OID (as will be the case for an unsupported
curve), then `explicit` encoding will be used.
* Allow specifying acceptable point formats when loading public keys
(this also fixes a minor bug where python-ecdsa would accept raw
encoding for points in PKCS8 files). Set of accepted encodings is controlled
by `valid_encodings` keyword argument in
`ECDH.load_received_public_key_bytes()`, `VerifyingKey.from_string()`,
`VerifyingKey.from_pem()`, VerifyingKey.from_der()`.
* `PointJacobi` and `Point` now inherit from `AbstractPoint` that implements
the methods for parsing points. That added `from_bytes()` and
`to_bytes()` methods to both of them.
* Curve parameters can now be read and written to PEM and DER files. The
`Curve` class supports new `to_der()`, `from_der()`, `to_pem()`, and
`from_pem()` methods.

Doc fix:
* Describe in detail which methods can raise `RSZeroError`, and that
`SigningKey.sign_deterministic()` won't raise it.

Bug fix:
* Correctly truncate hash values larger than the curve order (only impacted
custom curves and the curves added in this release).
* Correctly handle curves for which the order is larger than the prime
(only impacted custom curves and the secp160r1 curve added in this release).
* Fix the handling of `==` and `!=` for `Public_key`, `Private_key`, `Point`,
`PointJacobi`, `VerifyingKey`, and `SigningKey` so that it behaves
consistently and in the expected way both in Python 2 and Python 3.
* Implement lock-less algorithm inside PointJacobi for keeping shared state
so that when a calculation is aborted with KeyboardInterrupt, the state
doesn't become corrupted (this fixes the occasional breakage of ecdsa in
interactive shells).

New features:
* The `speed.py` script now provides performance for signature verification
without the use of precomputation.
* New curves supported: secp112r1, secp112r2, secp128r1, secp160r1.

Performance:
* Use 2-ary Non-Adjacent Form for the combined multiply-add. This speeds up
single-shot verify (i.e. without precomputation) by about 4 to 5%.
* Use native Python 3.8 support for calculating multiplicative inverses.

Maintenance:
* Include Python 3.9 in PyPI keywords.
* More realistic branch coverage counting (ignore Python version-specific
branches).
* Additional test coverage to many parts of the library.
* Migrate to Github Actions for Continuous Testing.

New API:
`VerifyingKey.precompute()` supports `lazy` argument to delay precomputation
to the first time the key is used to verify a signature.

Doc fixes:
Documentation for the `VerifyingKey.precompute()` method.

Bug fix:
Make created signatures correct when the hash used is bigger than the curve
order bit size and the curve order is not a multiple of 8 (this affects
only users of custom curves or hashes with output larger than 512 bits).

Performance:
Speed up library load time by calculating the generator point multiplication
tables the first time the points are used, not when they are initialised.

Maintenance:
Include Python 3.9 in CI testing.
Test coverage for the `VerifyingKey.precompute()` method.
Small speed-ups for the test suite.