const AES_GCM_ALGORITHM = 'AES-GCM';
const FILE_KEY_LENGTH = 256;256-bit key
const IV_BYTE_LENGTH = 12;
 
export const encryptFile = async (file: File): Promise<EncryptedFile> => {
  const key = await generateFileKey();A new key for every file
  const iv = generateRandomIv();
  const plaintext = await file.arrayBuffer();
  const ciphertext = await getSubtleCrypto().encrypt(Runs in your browser
    {
      iv: iv.slice().buffer,
      name: AES_GCM_ALGORITHM,
    },
    key,
    plaintext,
  );
 
  return {
    encryptedBlob: new Blob([ciphertext], { type: 'application/octet-stream' }),
    encryptionVersion: 'v1',
    iv,
    key,
  };
};