(WIP) feat: LWE

[Autoparallel]

WIP

• Basic LWE
• Ring-LWE
• Improve API (take bytes for Plaintext?)
• Improve documentation
• Better testing

[Autoparallel]

I can't replicate the failing test locally. Maybe an issue with toolchain?

[mrdaybird]

I can't replicate the failing test locally. Maybe an issue with toolchain?

Maybe rerun the tests, weil_from_test_pairing test occasionally fails for me as well, not sure why though.

[Autoparallel]

It's so odd. Drives me kinda crazy.

[mrdaybird]

LGTM. 👍
Would love to see it work for larger messages!

[mrdaybird]

Is this needed?
I think (result - q_half) <= (-result + q_half) for result >= q_half, and (q_half - result) <= (result + q_half) for result < q_half, is always true. I also did a quick check if this is ever not true for test_encryption_decryption.

Maybe you could verify this?

Maybe this could be distilled to:

Suggested change

	let dist_to_q_half = if result >= q_half {
	// If result ≥ q/2, distance is min(result - q/2, q - result + q/2)
	(result - q_half).min(-result + q_half)
	} else {
	// If result < q/2, distance is min(q/2 - result, result + q/2)
	(q_half - result).min(result + q_half)
	};
	let dist_to_q_half = (result - q_half).min(q_half - result);