index.js

import BN from 'bn.js';
import {bn2array,arraySize} from './lib/bn2array.js';
export * from "./lib/lwesetup.js";

function typeCheckBN(plainBigNum){
  if(!BN.isBN(plainBigNum)){
    throw new Error('Type Error: the input is not BN type');
  }
}

export function LWEencrypt(encryptor,plainBigNum,encoder){

  typeCheckBN(plainBigNum);
  var plainNumArray = bn2array(plainBigNum);
  
  const plainNumArrayEncode = encoder.encode(
    Uint32Array.from(plainNumArray)
  )
  return encryptor.encrypt(plainNumArrayEncode);
}

export function LWEaddMatrix(evaluator,cipherTexMatrix1,cipherTexMatrix2,seal){

  var cipherTexArray = [];
  for (let i=0;i<arraySize;i++){
    let cipherText = seal.CipherText();
    evaluator.add(cipherTexMatrix1[i], cipherTexMatrix2[i], cipherText)
    cipherTexArray.push(cipherText);
  }
  return {typeinfo:"cipherTexArray", contents:cipherTexArray};
}

export function LWEsmul(evaluator,encoder,cipherTex1,plainTexBN,seal){

  const plainArray = bn2array(plainTexBN);
 
  var cipherTexArray = [];
  for (let i=0;i<arraySize;i++){
    let array0 = [];
    for (let j=0;j<arraySize;j++){
      array0.push(plainArray[i]);
    }

    let plainTexArray = Uint32Array.from(array0);
    let plainTexArrayEncoded =encoder.encode(plainTexArray);
   
    let cipherText = seal.CipherText();
    evaluator.multiplyPlain(cipherTex1, plainTexArrayEncoded, cipherText);
    cipherTexArray.push(cipherText);
  }

  return {typeinfo:"cipherTextMetrix", contents:cipherTexArray};
}

export function decryptMatrixToBN(decryptor,matrix,encoder){

  var bn0 = new BN(0);
  for (let i=0;i<arraySize;i++){
      let intArray0 =  decryptor.decrypt(matrix[i]);
      let intArray = encoder.decode(intArray0);
      
      for (let j=0;j<arraySize;j++){
          let bn = new BN(intArray[j]);
          
          let bnMul = bn.mul(new BN("1".concat("00".repeat(i+j))));
          
          bn0 = bn0.add(bnMul);
      }
  }
  return bn0;
}