crypto: add fnv1a hash

[littledivy]

Like the one in std/hash https://github.com/denoland/deno_std/blob/main/hash/_fnv

[luk3skyw4lker]

I can take this one. I'll take a look at the algorithm today and create an implementation.

[luk3skyw4lker]

Why the need for them to be at the crypto module? Is it because it's internal? I didn't fully understand the need for it.

[KyleJune]

It's because hash module is deprecated (see top of README.md). They are going to delete the whole hash folder. Instead of deleting fnv that can't be replaced with WebCrypto and std/crypto, I think they are just going to just move it to std/crypto folder instead of keeping this folder with just fnv algorithms in it.

[luk3skyw4lker]

Dang! That totally slipped through me, I'm sorry!

I'll do the work of implementing the algorithms then, thanks for the heads up!

[KyleJune]

I think all the other ones in that directory can be done by WebCrypto or std/crypto. fnv is a non cryptographic hash, which is why it currently doesn't have a replacement. I'm not sure about internal discussions at Deno on this task, but I think the fnv implementation in hash could just be moved to std/crypto instead of re-implementing it.

[luk3skyw4lker]

I'm checking with the maintainers about the internals, thanks for your tips!

[littledivy]

Yup std/hash is deprecated so we need this in std/crypto. You can simply copy over the algorithm from std/hash/_fnv to expose this API:

import { crypto } from "https://deno.land/std/crypto/mod.ts";

// 32bit
await crypto.subtle.digest("fnv32", new TextEncoder().encode("deno")); // 0x6e, 0xd5, 0xa7, 0xa9
await crypto.subtle.digest("fnv32a", new TextEncoder().encode("deno")); // 0x8e, 0xf6, 0x47, 0x11

// 64bit
await crypto.subtle.digest("fnv64", new TextEncoder().encode("deno")); // 0x14, 0xed, 0xb2, 0x7e, 0xec, 0xda, 0xad, 0xc9
await crypto.subtle.digest("fnv64a", new TextEncoder().encode("deno")); // 0xa5, 0xd9, 0xfb, 0x67, 0x42, 0x6e, 0x48, 0xb1

The streaming implementation can also be simplified to a simple function, like the one used in std/http/file_server.ts https://github.com/denoland/deno_std/blob/main/http/file_server.ts#L183

[luk3skyw4lker]

Yeah, I was thinking about placing a function just like the one from std/http/file_server.ts at the mod.ts file of the crypto module. But then I took a deeper look at the module implementation and saw that most of the algorithms are placed in the _wasm_crypto module which is in Rust.

In that case, should I do the Typescript implementation or follow the pattern and implement them in Rust? (I'm almost sure that the Rust implementation should be the option)

[littledivy]

In that case, should I do the Typescript implementation or follow the pattern and implement them in Rust?

Typescript. The algorithm is fairly trivial and possibly more performant than WASM (calling into WASM each iteration is not cheap)

[luk3skyw4lker]

Right! Thanks for the answers, I'll try to make a PR today.

[kt3k]

done in #2200