feat(noise): deprecate non-compliant implementation

[thomaseizinger]

Description

For the last two years, we have been carrying around a non-compliant implementation of the noise protocol for libp2p. It is time to follow through on the announcement in that changelog entry and deprecate it. Users should use the spec compliant implementation instead.

1. This will reduce the maintenance effort of our codebase.
2. We will improve compile-times because we no longer need to depend on libsodium to test cryptography that is only part of the non-compliant implementation.
3. It will simplify usage of rust-libp2p because users cannot accidentally choose the wrong implementation.

Notes

Links to any relevant issues

Open Questions

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[mergify]

This pull request has merge conflicts. Could you please resolve them @thomaseizinger? 🙏

[mxinden]

Thanks @thomaseizinger. Good idea.

What do you think of deprecating LegacyConfig as well?

rust-libp2p/transports/noise/src/lib.rs

Lines 572 to 585 in 76abab9

	/// Legacy configuration options.
	#[derive(Clone, Copy, Default)]
	pub struct LegacyConfig {
	/// Whether to continue sending legacy handshake payloads,
	/// i.e. length-prefixed protobuf payloads inside a length-prefixed
	/// noise frame. These payloads are not interoperable with other
	/// libp2p implementations.
	pub send_legacy_handshake: bool,
	/// Whether to support receiving legacy handshake payloads,
	/// i.e. length-prefixed protobuf payloads inside a length-prefixed
	/// noise frame. These payloads are not interoperable with other
	/// libp2p implementations.
	pub recv_legacy_handshake: bool,
	}

[mxinden]

https://github.com/libp2p/rust-libp2p/blob/master/CHANGELOG.md#version-0190-2020-05-18

Great changelog spelunking!

[thomaseizinger]

Thanks @thomaseizinger. Good idea.

What do you think of deprecating LegacyConfig as well?

rust-libp2p/transports/noise/src/lib.rs

Lines 572 to 585 in 76abab9

	/// Legacy configuration options.
	#[derive(Clone, Copy, Default)]
	pub struct LegacyConfig {
	/// Whether to continue sending legacy handshake payloads,
	/// i.e. length-prefixed protobuf payloads inside a length-prefixed
	/// noise frame. These payloads are not interoperable with other
	/// libp2p implementations.
	pub send_legacy_handshake: bool,
	/// Whether to support receiving legacy handshake payloads,
	/// i.e. length-prefixed protobuf payloads inside a length-prefixed
	/// noise frame. These payloads are not interoperable with other
	/// libp2p implementations.
	pub recv_legacy_handshake: bool,
	}

Yep, that is a good one to remove too! I'll send a PR.