@transcend-io/penumbra

Usage

Display an encrypted file

// Decrypt and display text
getDecryptedContent(fileUrl, key, iv, authTag, 'text/plain')
  .then(decryptedText => {
    document.getElementById('my-paragraph').innerText = decryptedText;
  });

// Decrypt and display media
getDecryptedContent(url, key, iv, authTag, 'image/jpeg')
  .then(imageSrc => {
    document.getElementById('my-img').src = imageSrc;
  });

Download an encrypted file

downloadEncryptedFile(
  `https://s3-us-west-2.amazonaws.com/bencmbrook/africa.topo.json.enc`,
  key,
  iv,
  authTag,
  {
    fileName: 'myFile.json', // optional values
    progressEventName: 'download-progress' // defaults to the url
  }
);

Download Progress Event Emitter

You can listen to a download progress event. The event type is the same as the url parameter

window.addEventListener(url, e => {
  console.log(`${e.detail}% done`);
});

Note: this feature requires the Content-Length response header to be exposed. This works by adding Access-Control-Expose-Headers: Content-Length to the response header (read more here and here)

On Amazon S3, this means adding the following line to your bucket policy, inside the <CORSRule> block:

<ExposeHeader>Content-Length</ExposeHeader>