shifro

A lightweight library for decrypting MP4 files, directly in the browser

Installation

Install library as dependency for your project:

npm install shifro

Install globally to use as command-line tool:

npm install -g shifro

Usage

Library

Decrypting file using browser's Web Streams API

import { Input, StreamSource, Output, StreamTarget, Decryption } from 'shifro';

const selectFile = async () =>
  new Promise<File>((resolve) => {
    const input = document.querySelector<HTMLInputElement>('#input')!;
    input.addEventListener('change', () => resolve(input.files![0]));
  });

async function main() {
  const inputFile = await selectFile();
  const inputStream = inputFile.stream();

  const outputFileHandle = window.showSaveFilePicker({ suggestedName: 'output.mp4', startIn: 'downloads' });
  const outputStream = await outputFileHandle.createWritable();

  const input = new Input({ source: new StreamSource(inputStream) });
  const output = new Output({ target: new StreamTarget(outputStream) });
  const decryption = await Decryption.init({
    input,
    output,
    keys: [
      {
        kid: 'eb676abbcb345e96bbcf616630f1a3da',
        key: '100b6c20940f779a4589152b57d2dacb',
      },
    ],
    onProgress: (progress) => console.log(`Decrypting... ${progress}`),
  });
  await decryption.execute();
}

Decrypting file using Node.js streams

import { Input, FilePathSource, Output, FilePathTarget, Decryption } from 'shifro';

async function main() {
  const input = new Input({ source: new FilePathSource('./input.mp4') });
  const output = new Output({ target: new FilePathTarget('./output.mp4') });
  const decryption = await Decryption.init({
    input,
    output,
    keys: [
      {
        kid: 'eb676abbcb345e96bbcf616630f1a3da',
        key: '100b6c20940f779a4589152b57d2dacb',
      },
    ],
    onProgress: (progress) => process.stdout.write(`\rDecrypting... [${progress}]`),
  });
  await decryption.execute();
}

CLI

shifro --key eb676abbcb345e96bbcf616630f1a3da:100b6c20940f779a4589152b57d2dacb ./input.mp4 ./output.mp4

Credits

• mp4box.js
• mediabunny