After working on this on and off for 7 days, I've finally finished implementing NIP-44 encryption in Swift for use on Apple platforms! This will replace the unrecommended NIP-04 encryption. Definitely lost a few hairs and gained a few gray ones. 😅 Thanks to nostr:npub1qlk0nqupxmlyxravg0aqscxmcc4q4tq898z6x003rykwwh3npj0syvyayc for reviewing my PR to Nostr SDK for Apple Platforms and thanks to nostr:npub16zsllwrkrwt5emz2805vhjewj6nsjrw0ge0latyrn2jv5gxf5k0q5l92l7 from Nos for pair programming with me when I got stuck.
https://github.com/nostr-sdk/nostr-sdk-ios/pull/138

I’ve submitted a forked copy to the shared nip44 repo. Please review and double-check my work if you’re able to read Swift code. All the test vectors pass, though. nostr:npub10jcnehsxwrjepupvh602pl83up0dh3wv3fqfwv062smygqvpeuwsk03kag nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z nostr:npub1acg6thl5psv62405rljzkj8spesceyfz2c32udakc2ak0dmvfeyse9p35c 
https://github.com/paulmillr/nip44/pull/11