fix(ext/node): add aes256 algorithm support

[iuioiua]

Please excuse any silly mistakes. I have little experience with the Node compatibility layer and crypto.

Towards #21804

CC @littledivy

[iuioiua]

How do I come up with test data for the corresponding createDecipheriv() test?

[littledivy]

I'm not sure how the test vectors were generated for createDecipheriv().

I think this should work:

# Encrypts null 10byte plaintext using zeroed key and IV and hex encodes it.
echo 0000000000 \
 | openssl enc -e -aes256 -K 0000000000000000000000000000000000000000000000000000000000000000 -iv 00000000000000000000000000000000 \
 | xxd -p

Add the output of the command as the input in the 'aes256' createDecipheriv test

@kt3k Do you know how they were created?

[kt3k]

I think I've used the same API of Node.js to create them

[iuioiua]

Ah, got it using:

const { createCipheriv } = require('node:crypto');

const cipher = createCipheriv("aes256", zeros(32), zeros(16));
const input = cipher.update(zeros(90), undefined, "hex") + cipher.final("hex");

[littledivy]

LGTM