EndtoEnd.js

const key = crypto.subtle
  .generateKey(
    {
      name: "RSA-OAEP",
      modulusLength: 2048,
      publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
      hash: "SHA-256",
    },
    false,
    ["encrypt", "decrypt"]
  )
  .then((k) => {
    console.log('keys generated')
    return k;
  });
const pubKeys = {};
onmessage = async function (e) {
  const data = e.data;
  const opr = data.operation;
  if (opr == 0) {         //export the pub key
    const publicKey = await crypto.subtle.exportKey(
      "jwk",
      (
        await key
      ).publicKey
    );
    self.postMessage({ operation: 0, key: publicKey });
  } else if (opr == 1) {  //import the pub key
    if (!data.key){
      delete pubKeys[data.server+data.id]
      return
    }
    const publicKey = await crypto.subtle.importKey(
      "jwk",
      {
        kty: "RSA",
        n: data.key,
        e: "AQAB",
        ext: true,
        key_ops: ["encrypt"],
      },
      { name: "RSA-OAEP", hash: "SHA-256" },
      true,
      ["encrypt"]
    );
    pubKeys[data.server + data.id] = publicKey;
    console.log("pub key set for " + data.server + data.id);
  } else if (opr == 2) {  //encrypt msg
    if (data.server + data.id in pubKeys) {
      // encrypt using the publicKey by updating the msg key
      data['present']=true
      const msgbuffer = new TextEncoder().encode(data.msg);
      const encmsgbuffer = await crypto.subtle.encrypt(
        { name: "RSA-OAEP" },
        pubKeys[data.server + data.id],
        msgbuffer
      );
      data.msg = btoa(String.fromCharCode(...new Uint8Array(encmsgbuffer)));
      self.postMessage(data);
    } else {
      data['present']=false
      self.postMessage(data);
    }
  } else if (opr == 3) {  //decrypt msg
    const encmsgbuffer = new Uint8Array(
      atob(data.msg)
        .split("")
        .map((c) => c.charCodeAt(0))
    );
    const dcrptmsgbuffer = await crypto.subtle.decrypt(
      { name: "RSA-OAEP" },
      (
        await key
      ).privateKey,
      encmsgbuffer
    );
    data.msg = new TextDecoder().decode(dcrptmsgbuffer);
    self.postMessage(data);
  }
};