Not implemented: crypto.generateKeyPairSync

I don't understand why I'm getting this error. The code is:

import { generateKeyPairSync } from "https://deno.land/std@0.177.0/node/crypto.ts";
console.log(generateKeyPairSync("ed25519"));

import { generateKeyPairSync } from "https://deno.land/std@0.177.0/node/crypto.ts";
console.log(generateKeyPairSync("ed25519"));

import { generateKeyPairSync } from "https://deno.land/std@0.177.0/node/crypto.ts";
console.log(generateKeyPairSync("ed25519"));

import { generateKeyPairSync } from "https://deno.land/std@0.177.0/node/crypto.ts";
console.log(generateKeyPairSync("ed25519"));