PQC Algorithm Comparison

// ML-KEM Key Encapsulation (Conceptual Example)
// Use a NIST-validated library like liboqs, PQClean, or AWS-LC

import { ML_KEM_768 } from '@example/pqc-lib';

// 1. Key Generation (receiver generates keypair)
const { publicKey, secretKey } = ML_KEM_768.keygen();
// publicKey: 1184 bytes | secretKey: 2400 bytes

// 2. Encapsulation (sender creates shared secret)
const { ciphertext, sharedSecret } = ML_KEM_768.encaps(publicKey);
// ciphertext: 1088 bytes | sharedSecret: 32 bytes

// 3. Decapsulation (receiver recovers shared secret)
const recoveredSecret = ML_KEM_768.decaps(ciphertext, secretKey);
// recoveredSecret === sharedSecret (32 bytes)

// 4. Use sharedSecret for symmetric encryption (AES-256-GCM)
const encrypted = AES_GCM.encrypt(plaintext, sharedSecret, nonce);

// ML-DSA Digital Signatures (Conceptual Example)
// Use a NIST-validated library for production

import { ML_DSA_65 } from '@example/pqc-lib';

// 1. Key Generation (signer generates keypair)
const { publicKey, secretKey } = ML_DSA_65.keygen();
// publicKey: 1952 bytes | secretKey: 4032 bytes

// 2. Sign a message
const message = new TextEncoder().encode('Document to sign');
const signature = ML_DSA_65.sign(message, secretKey);
// signature: 3293 bytes

// 3. Verify signature (anyone with publicKey)
const isValid = ML_DSA_65.verify(message, signature, publicKey);
// isValid: true if signature is authentic

// Common use cases:
// - Code signing and software updates
// - Document authentication
// - Certificate authorities (X.509)
// - Blockchain and smart contracts

// Hybrid Key Exchange (Defense in Depth)
// Combines classical and post-quantum algorithms

import { X25519, ML_KEM_768, HKDF_SHA256 } from '@example/crypto-lib';

// Classical component (X25519 ECDH)
const classicalKeyPair = X25519.generateKeyPair();
const classicalShared = X25519.computeShared(
  classicalKeyPair.secretKey,
  peerClassicalPublic
);

// Post-quantum component (ML-KEM)
const { ciphertext, sharedSecret: pqShared } = ML_KEM_768.encaps(
  peerPQPublic
);

// Combine both secrets using KDF
const hybridSecret = HKDF_SHA256.derive(
  [...classicalShared, ...pqShared],  // Combined input
  salt,
  'hybrid-tls-secret',
  32  // Output length
);

// Hybrid provides security even if one algorithm is broken