Cloudflare Developers•11mo ago

worker crypto

i wast trying to implement api to in cloudflare worker to generate deviceId but my function uses crypto library and i don't find the same function in cloudflare crypto:

using nodejs crypto lib.

function getDeviceI() {
  let id = crypto.randomBytes(20).toString("binary");
  let hmac = crypto.createHmac(
    "sha1",
    Buffer.from(
      "E7309ECC0953C6FA60005B2765F99DBBC965C8E9",
      "hex"
    )
  );
  hmac.update(Buffer.from(Buffer.from("19", "hex") + id, "binary"));
  return "19" + Buffer.from(id, "binary").toString("hex") + hmac.digest("hex");
}
correct deviceId:19CEB4EB9340402020E054720BEBAF280A8CEA373CC6E00629C9CEB1B3CB14FD5ABC0D4F5896DBAD4E

using nodejs crypto lib.

function getDeviceI() {
  let id = crypto.randomBytes(20).toString("binary");
  let hmac = crypto.createHmac(
    "sha1",
    Buffer.from(
      "E7309ECC0953C6FA60005B2765F99DBBC965C8E9",
      "hex"
    )
  );
  hmac.update(Buffer.from(Buffer.from("19", "hex") + id, "binary"));
  return "19" + Buffer.from(id, "binary").toString("hex") + hmac.digest("hex");
}
correct deviceId:19CEB4EB9340402020E054720BEBAF280A8CEA373CC6E00629C9CEB1B3CB14FD5ABC0D4F5896DBAD4E

can anyone help

4 Replies

Steved•11mo ago

As per inline comment, did you try: https://developers.cloudflare.com/workers/runtime-apis/web-crypto/ ?

Web Crypto · Cloudflare Workers docs

The Web Crypto API provides a set of low-level functions for common cryptographic tasks. The Workers Runtime implements the full surface of this API, …

bᥲkᥙg᥆•11mo ago

async function getDeviceID() {
  const randomBytes = new Uint8Array(20);
  crypto.getRandomValues(randomBytes);
  const id = Array.from(randomBytes, byte => byte.toString(16).padStart(2, '0')).join('');

  const secretKeyHex = "E7309ECC0953C6FA60005B2765F99DBBC965C8E9";
  const secretKeyBuffer = new TextEncoder().encode(secretKeyHex);

  const hmacKey = await crypto.subtle.importKey("raw", secretKeyBuffer, { name: "HMAC", hash: { name: "SHA-1" } }, false, ["sign"]);

  const data = new TextEncoder().encode("19" + id);
  const hmac = await crypto.subtle.sign("HMAC", hmacKey, data);

  const hmacHex = Array.from(new Uint8Array(hmac)).map(byte => byte.toString(16).padStart(2, '0')).join('');

  const deviceIdentifier = "19" + id + hmacHex;

  return deviceIdentifier;
}

export default {
  async fetch(request, env, ctx) {
    return new Response(await getDeviceID());
  },
};

async function getDeviceID() {
  const randomBytes = new Uint8Array(20);
  crypto.getRandomValues(randomBytes);
  const id = Array.from(randomBytes, byte => byte.toString(16).padStart(2, '0')).join('');

  const secretKeyHex = "E7309ECC0953C6FA60005B2765F99DBBC965C8E9";
  const secretKeyBuffer = new TextEncoder().encode(secretKeyHex);

  const hmacKey = await crypto.subtle.importKey("raw", secretKeyBuffer, { name: "HMAC", hash: { name: "SHA-1" } }, false, ["sign"]);

  const data = new TextEncoder().encode("19" + id);
  const hmac = await crypto.subtle.sign("HMAC", hmacKey, data);

  const hmacHex = Array.from(new Uint8Array(hmac)).map(byte => byte.toString(16).padStart(2, '0')).join('');

  const deviceIdentifier = "19" + id + hmacHex;

  return deviceIdentifier;
}

export default {
  async fetch(request, env, ctx) {
    return new Response(await getDeviceID());
  },
};

not generating the correct deviceId

from base64 import b64decode, b64encode
from typing import Union
from hashlib import sha1
from hmac import new

PREFIX = bytes.fromhex("19")
SIG_KEY = bytes.fromhex("DFA5ED192DDA6E88A12FE12130DC6206B1251E44")
DEVICE_KEY = bytes.fromhex("E7309ECC0953C6FA60005B2765F99DBBC965C8E9")

def gen_deviceId(data: bytes = None) -> str:
    if isinstance(data, str): data = bytes(data, 'utf-8')
    identifier = PREFIX + (data or os.urandom(20))
    mac = new(DEVICE_KEY, identifier, sha1)
    return f"{identifier.hex()}{mac.hexdigest()}".upper()

from base64 import b64decode, b64encode
from typing import Union
from hashlib import sha1
from hmac import new

PREFIX = bytes.fromhex("19")
SIG_KEY = bytes.fromhex("DFA5ED192DDA6E88A12FE12130DC6206B1251E44")
DEVICE_KEY = bytes.fromhex("E7309ECC0953C6FA60005B2765F99DBBC965C8E9")

def gen_deviceId(data: bytes = None) -> str:
    if isinstance(data, str): data = bytes(data, 'utf-8')
    identifier = PREFIX + (data or os.urandom(20))
    mac = new(DEVICE_KEY, identifier, sha1)
    return f"{identifier.hex()}{mac.hexdigest()}".upper()

here is equivalant code in python

cg•11mo ago

Would crypto.randomUUID() suffice?

bᥲkᥙg᥆•11mo ago

nah i have to generate valid deviceId since it's being used in api

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worker crypto