title: Making a unique extension id and key for Chrome extension?
body: <p>I have a Chrome extension I made, but based it on some example found online.  Its not in a crx file.  The extension ID is the one used in the example.  I would like to change it before I upload my extension to the chrome store.  My question is how do I change this?  Do I just manually change the letters in my manifest.json file?  Or does the extension id have to be generated from something because its in a fixed format?  Same for the key, can I just randomly change these two before I do anything else now that I'm ready?</p>
  
  <pre><code>{
    // Extension ID: rnldjzfmornpzlahmmmgbagdohdnhdic
    "key": "MIGfMA3GCSqGSIb3DFEBAQUAA4GNADCBiQKBgQDcBHwzDvyBQ6bDppkIs9MP4ksKqCMyXQ/A52JivHZKh4YO/9vJsT3oaZhSpDCE9RCocOEQvwsHsFReW2nUEc6OLLyoCFFxIb7KkLGsmfakkut/fFdNJYh0xOTbSN8YvLWcqph09XAY2Y/f0AL7vfO1cuCqtkMt8hFrBGWxDdf9CQIDAQAB",
    "name": "Name of extension",
  ...
  </code></pre>