Sound is the
new Bluetooth.

# Install via npm (requires API key)
npm install @eltav/acoustic-bridge

# Or load via CDN (beta)
<script src="https://sdk.eltav.io/cdn/acoustic-bridge@1.0.0.min.js"></script>

# Initialize with your API key
const bridge = await AcousticBridge.init({
  apiKey: 'eltav_pk_your_key_here',
  mode: 'ultrasonic', // or 'audible' for demo/debug
  sampleRate: 44100
});

import { AcousticTransmitter, ULTRASONIC_SCALE } from '@eltav/acoustic-bridge';

// Create a transmitter (requires user gesture for AudioContext)
const tx = new AcousticTransmitter({
  frequencies: ULTRASONIC_SCALE, // [18600, 19200, 19800, 20400]
  baudDuration: 0.08,            // 80ms per symbol
  rampDuration: 0.005,           // 5ms fade in/out to prevent clicks
  useHamming: true               // Hamming SECDED error correction
});

// Transmit a UTF-8 string
await tx.send('Hello from ELTAV SDK');
console.log('Transmitted successfully');

// Or send raw bytes
await tx.sendBytes(new Uint8Array([0x48, 0x69]));

import { AcousticReceiver, AcousticVisualizer } from '@eltav/acoustic-bridge';

// Request mic access and start listening
const rx = new AcousticReceiver({
  onMessage: (msg) => console.log('Received:', msg),
  onError:   (err) => console.error('Decode error:', err),
  onSnr:     (snr) => console.log('SNR:', snr, 'dB')
});

await rx.start(); // triggers mic permission prompt

// Optional: attach live spectrum visualizer
const viz = new AcousticVisualizer(rx, {
  canvas: document.getElementById('myCanvas'),
  colorHot: '#00e5ff',
  colorBg: '#03050a'
});

viz.start(); // begins animating at 60fps

import { generateKeyPair, powerMod, simpleHash } from '@eltav/acoustic-bridge';

// --- Device A (Prover) ---
const { x, y } = generateKeyPair(); // x = secret, y = public key

// Transmit public key y acoustically to Device B
await tx.send(y.toString());

// Receive challenge c from Device B
const c = simpleHash(await rx.receive());

// Compute Schnorr response s = (r - c*x) mod q
const s = (r - c * x) % Q;
await tx.send(s.toString());

// --- Device B (Verifier) ---
// Verify: check t === g^s * y^c mod P
const check = (powerMod(G, s, P) * powerMod(y, c, P)) % P;
const verified = check === t;
console.log('Proximity verified:', verified); // true only if physically present