Full Example

CommonJS (but also works with import)

import SEAL from 'node-seal'

// load wasm
const seal = await SEAL()

// ----- 1. params/context -----
const scheme = seal.SchemeType.bfv
const security = seal.SecLevelType.tc128
const polyModulusDegree = 4096

const parms = new seal.EncryptionParameters(scheme)
parms.setPolyModulusDegree(polyModulusDegree)
parms.setCoeffModulus(seal.CoeffModulus.BFVDefault(polyModulusDegree, security))
parms.setPlainModulus(seal.PlainModulus.Batching(polyModulusDegree, 20))

const context = new seal.SEALContext(parms, true, security)
if (!context.parametersSet()) {
  throw new Error('SEAL context: invalid parameters')
}

// ----- 2. helpers / keys -----
const encoder = new seal.BatchEncoder(context)
const keygen = new seal.KeyGenerator(context)
const publicKey = keygen.createPublicKey()
const secretKey = keygen.secretKey()

const encryptor = new seal.Encryptor(context, publicKey)
const decryptor = new seal.Decryptor(context, secretKey)
const evaluator = new seal.Evaluator(context)

// ----- 3. encode + encrypt -----
const data = BigInt64Array.from([1n, 2n, 3n, 4n, 5n])

const plain = new seal.Plaintext()
encoder.encode(data, plain)

const cipher = new seal.Ciphertext()
encryptor.encrypt(plain, cipher)

// ----- 4. operate on ciphertext -----
evaluator.addInplace(cipher, cipher) // ciphertext = ciphertext + ciphertext

// ----- 5. decrypt + decode -----
decryptor.decrypt(cipher, plain)
const decoded = encoder.decodeBigInt64(plain)

console.log('decoded:', decoded)