Zero-Knowledge Key Rotation & Order-Revealing Encryption (ORE)

FLASH DB provides defense-in-depth cryptographic primitives for long-term database security and confidential range queries on encrypted ciphertexts.

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1. Envelope Encryption & Key Rotation (FlashKeyRotationManager)

Envelope encryption uses a Master Key (KEK - Key Encryption Key) to govern versioned Data Encryption Keys (DEKs).

Ciphertexts include their version envelope: flash:v<version>:<iv>:<authTag>:<ciphertext>.

Features

• Zero-Downtime Key Rotation: Rotate keys seamlessly while older keys remain available for reading older records.
• Lazy Re-encryption: Documents are automatically re-encrypted with the latest active key during read/update operations.
• Batch Migration: Seamlessly re-encrypt millions of documents in background batches.

import { FlashKeyRotationManager } from 'flash-zk';

const keyManager = new FlashKeyRotationManager('master_quantum_secret_2026');

// 1. Encrypt with Version 1
const v1Cipher = keyManager.encrypt({ ssn: '000-12-3456', salary: 120000 });
console.log(v1Cipher); // 'flash:v1:a8f9...:b3c1...:90ef...'

// 2. Rotate to Version 2
keyManager.rotateKey();

// 3. Encrypt new document with Version 2
const v2Cipher = keyManager.encrypt({ ssn: '000-98-7654', salary: 95000 });
console.log(v2Cipher); // 'flash:v2:77da...:44ea...:55fb...'

// 4. Decrypt both seamlessly
console.log(keyManager.decrypt(v1Cipher)); // { ssn: '000-12-3456', salary: 120000 }
console.log(keyManager.decrypt(v2Cipher)); // { ssn: '000-98-7654', salary: 95000 }

// 5. Check if a record requires re-encryption
if (keyManager.needsReEncryption(v1Cipher)) {
  const upgradedCipher = keyManager.reEncrypt(v1Cipher);
  console.log(upgradedCipher); // Now upgraded to 'flash:v2:...'!
}

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2. Order-Revealing Encryption (FlashORE)

FlashORE enables servers to evaluate comparison and range operators ($gt, $gte, $lt, $lte, $between) directly over encrypted ciphertext tokens without decrypting the underlying numbers or dates.

How It Works

1. The client SDK encrypts numbers into ORE tokens before sending them to the database.
2. The server compares ORE tokens in constant $O(1)$ time to filter records.
3. The server never learns the plaintext numbers, account balances, or timestamps!

import { FlashORE } from 'flash-zk';

const ore = new FlashORE('secret_field_prf_key');

// Encrypt plain values on the client side
const oreSalaryMin = ore.encrypt(50000, 'salary');
const oreSalaryMax = ore.encrypt(100000, 'salary');
const oreDocSalary = ore.encrypt(75000, 'salary');

// Server-side Range Evaluation (Without decrypting!)
const matches = FlashORE.matchesRange(oreDocSalary, {
  $gt: oreSalaryMin,
  $lt: oreSalaryMax
});

console.log(matches); // true!

// Direct Token Comparison
console.log(FlashORE.compare(oreSalaryMin, oreSalaryMax)); // -1 (Min < Max)