Page dies when encrypting large files

[chiahsoon]

Hi! I'm trying to encrypt large file sizes (>= 1 GB) using AES-GCM, but when i try to upload a 1GB file, the page dies before finishing the encryption.

Pretty sure i'm missing some relevant javascript concepts here but any direction/help will be very much appreciated! My code currently looks something like this:

  // arrBuf represents file.arrayBuffer();
  const cipher = forge.cipher.createCipher('AES-GCM', key);
  cipher.start({
      iv: iv,
      additionalData: '',
      tagLength: 128,
  });
  const chunkSize = 1024 * 64;
  for (let idx = 0; idx < arrBuf.byteLength; idx += chunkSize) {
      const slice = arrBuf.slice(idx, idx + chunkSize);
      cipher.update(forge.util.createBuffer(slice)); 
  }
  cipher.finish();

[PierreJeanjacquot]

Hi @chiahsoon, I see 2 issues:

• your whole file is placed in an array buffer living in the heap, you may want to use a readable stream to keep the heap low while processing the file encryption.
• when you call cipher.update(chunkBuffer) you add the chunk to the cipher buffer making it grow with each new chunk, you can use cipher.output.getBytes() to flush the cipher buffer, you will get the current encryption state (write it or pass it to a stream).