Security and Encryption Libraries

Privacy requires security. Modern encryption libraries provide the cryptographic primitives needed for protecting personal data. libsodium offers a high-level, easy-to-use interface for encryption, decryption, signatures, and password hashing. For JavaScript applications, the Web Crypto API provides native browser encryption capabilities.

// Using libsodium for privacy-focused encryption
const sodium = require('libsodium-wrappers');

class PrivacyEncryption {
  async init() {
    await sodium.ready;
  }
  
  generateKeyPair() {
    // Generate key pair for user
    return sodium.crypto_box_keypair();
  }
  
  encryptForUser(message, recipientPublicKey, senderSecretKey) {
    // Encrypt message for specific user
    const nonce = sodium.randombytes_buf(sodium.crypto_box_NONCEBYTES);
    const encrypted = sodium.crypto_box_easy(
      message,
      nonce,
      recipientPublicKey,
      senderSecretKey
    );
    
    return {
      encrypted: sodium.to_base64(encrypted),
      nonce: sodium.to_base64(nonce)
    };
  }
  
  encryptSensitiveData(data, key) {
    // Encrypt sensitive data with authenticated encryption
    const nonce = sodium.randombytes_buf(sodium.crypto_secretbox_NONCEBYTES);
    const message = JSON.stringify(data);
    
    const encrypted = sodium.crypto_secretbox_easy(
      message,
      nonce,
      key
    );
    
    return {
      encrypted: sodium.to_base64(encrypted),
      nonce: sodium.to_base64(nonce)
    };
  }
  
  hashPassword(password) {
    // Hash password with salt
    return sodium.crypto_pwhash_str(
      password,
      sodium.crypto_pwhash_OPSLIMIT_INTERACTIVE,
      sodium.crypto_pwhash_MEMLIMIT_INTERACTIVE
    );
  }
  
  deriveKeyFromPassword(password, salt) {
    // Derive encryption key from password
    return sodium.crypto_pwhash(
      sodium.crypto_secretbox_KEYBYTES,
      password,
      salt,
      sodium.crypto_pwhash_OPSLIMIT_INTERACTIVE,
      sodium.crypto_pwhash_MEMLIMIT_INTERACTIVE,
      sodium.crypto_pwhash_ALG_DEFAULT
    );
  }
}

// Using Web Crypto API for browser-based encryption
class BrowserPrivacyEncryption {
  async generateKey() {
    return await crypto.subtle.generateKey(
      {
        name: 'AES-GCM',
        length: 256
      },
      true, // extractable
      ['encrypt', 'decrypt']
    );
  }
  
  async encryptData(data, key) {
    const encoder = new TextEncoder();
    const iv = crypto.getRandomValues(new Uint8Array(12));
    
    const encrypted = await crypto.subtle.encrypt(
      {
        name: 'AES-GCM',
        iv: iv
      },
      key,
      encoder.encode(JSON.stringify(data))
    );
    
    return {
      encrypted: btoa(String.fromCharCode(...new Uint8Array(encrypted))),
      iv: btoa(String.fromCharCode(...iv))
    };
  }
  
  async hashData(data) {
    const encoder = new TextEncoder();
    const hashBuffer = await crypto.subtle.digest(
      'SHA-256',
      encoder.encode(data)
    );
    
    return btoa(String.fromCharCode(...new Uint8Array(hashBuffer)));
  }
}