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x/openpgp/test/general/biginteger.js

OpenPGP implementation for JavaScript
openpgpjs/openpgpjs
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const random = require('../../src/crypto/random');const util = require('../../src/util');
const BN = require('bn.js');const chai = require('chai');chai.use(require('chai-as-promised'));
const expect = chai.expect;let BigInteger;
async function getRandomBN(min, max) {  if (max.cmp(min) <= 0) {    throw new Error('Illegal parameter value: max <= min');  }
  const modulus = max.sub(min);  const bytes = modulus.byteLength();  const r = new BN(await random.getRandomBytes(bytes + 8));  return r.mod(modulus).add(min);}
module.exports = () => describe('BigInteger interface', function() {  before(async () => {    BigInteger = await util.getBigInteger();  });
  it('constructor throws on undefined input', function() {    expect(() => new BigInteger()).to.throw('Invalid BigInteger input');  });

  it('constructor supports strings', function() {    const input = '417653931840771530406225971293556769925351769207235721650257629558293828796031115397206059067934284452829611906818956352854418342467914729341523414945427019410284762464062112274326172407819051167058569790660930309496043254270888417520676082271432948852231332576271876251597199882908964994070268531832274431027';    const got = new BigInteger(input);    const expected = new BN(input);    expect(got.toString()).to.equal(expected.toString());  });
  it('constructor supports Uint8Arrays', function() {    const expected = new BN('417653931840771530406225971293556769925351769207235721650257629558293828796031115397206059067934284452829611906818956352854418342467914729341523414945427019410284762464062112274326172407819051167058569790660930309496043254270888417520676082271432948852231332576271876251597199882908964994070268531832274431027');    const input = expected.toArrayLike(Uint8Array);    const got = new BigInteger(input);    expect(got.toString()).to.equal(expected.toString());  });
  it('conditional operators are correct', function() {    const a = new BigInteger(12);    const b = new BigInteger(34);
    expect(a.equal(a)).to.be.true;    expect(a.equal(b)).to.be.false;    expect(a.gt(a) === a.lt(a)).to.be.true;    expect(a.gt(b) === a.lt(b)).to.be.false;    expect(a.gte(a) === a.lte(a)).to.be.true;
    const zero = new BigInteger(0);    const one = new BigInteger(1);    expect(zero.isZero()).to.be.true;    expect(one.isZero()).to.be.false;
    expect(one.isOne()).to.be.true;    expect(zero.isOne()).to.be.false;
    expect(zero.isEven()).to.be.true;    expect(one.isEven()).to.be.false;
    expect(zero.isNegative()).to.be.false;    expect(zero.dec().isNegative()).to.be.true;  });
  it('bitLength is correct', function() {    const n = new BigInteger(127);    let expected = 7;    expect(n.bitLength() === expected).to.be.true;    expect(n.inc().bitLength() === (++expected)).to.be.true;  });
  it('byteLength is correct', function() {    const n = new BigInteger(65535);    let expected = 2;    expect(n.byteLength() === expected).to.be.true;    expect(n.inc().byteLength() === (++expected)).to.be.true;  });
  it('toUint8Array is correct', function() {    const nString = '417653931840771530406225971293556769925351769207235721650257629558293828796031115397206059067934284452829611906818956352854418342467914729341523414945427019410284762464062112274326172407819051167058569790660930309496043254270888417520676082271432948852231332576271876251597199882908964994070268531832274431027';    const n = new BigInteger(nString);    const paddedSize = Number(n.byteLength()) + 1;    // big endian, unpadded    let expected = new BN(nString).toArrayLike(Uint8Array);    expect(n.toUint8Array()).to.deep.equal(expected);    // big endian, padded    expected = new BN(nString).toArrayLike(Uint8Array, 'be', paddedSize);    expect(n.toUint8Array('be', paddedSize)).to.deep.equal(expected);    // little endian, unpadded    expected = new BN(nString).toArrayLike(Uint8Array, 'le');    expect(n.toUint8Array('le')).to.deep.equal(expected);    //little endian, padded    expected = new BN(nString).toArrayLike(Uint8Array, 'le', paddedSize);    expect(n.toUint8Array('le', paddedSize)).to.deep.equal(expected);  });
  it('binary operators are consistent', function() {    const a = new BigInteger(12);    const b = new BigInteger(34);    const ops = ['add', 'sub', 'mul', 'mod', 'leftShift', 'rightShift'];    ops.forEach(op => {      const iop = `i${op}`;      expect(a[op](b).equal(a[iop](b))).to.be.true;    });  });
  it('unary operators are consistent', function() {    const a = new BigInteger(12);    const one = new BigInteger(1);    expect(a.sub(one).equal(a.dec())).to.be.true;    expect(a.add(one).equal(a.inc())).to.be.true;  });
  it('modExp is correct (large values)', function() {    const stringX = '417653931840771530406225971293556769925351769207235721650257629558293828796031115397206059067934284452829611906818956352854418342467914729341523414945427019410284762464062112274326172407819051167058569790660930309496043254270888417520676082271432948852231332576271876251597199882908964994070268531832274431027';    const stringE = '21139356010872569239159922781526379521587348169074209285187910481667533072168468011617194695181255483288792585413365359733692097084373249198758148704369207793873998901870577262254971784191473102265830193058813215898765238784670469696574407580179153118937858890572095234316482449291777882525949871374961971753';    const stringN = '129189808515414783602892982235788912674846062846614219472827821758734760420002631653235573915244294540972376140705505703576175711417114803419704967903726436285518767606681184247119430411311152556442947708732584954518890222684529678365388350886907287414896703685680210648760841628375425909680236584021041565183';    const x = new BigInteger(stringX);    const e = new BigInteger(stringE);    const n = new BigInteger(stringN);
    const got = x.modExp(e, n);    const expected = new BN(stringX).toRed(BN.red(new BN(stringN))).redPow(new BN(stringE));    // different formats, it's easier to compare strings    expect(got.toString() === expected.toString()).to.be.true;  });
  it('gcd is correct', async function() {    const aBN = await getRandomBN(new BN(2), new BN(200));    const bBN = await getRandomBN(new BN(2), new BN(200));    if (aBN.isEven()) aBN.iaddn(1);    const a = new BigInteger(aBN.toString());    const b = new BigInteger(bBN.toString());    const expected = aBN.gcd(bBN);    expect(a.gcd(b).toString()).to.equal(expected.toString());  });
  it('modular inversion is correct', async function() {    const moduloBN = new BN(229); // this is a prime    const baseBN = await getRandomBN(new BN(2), moduloBN);    const a = new BigInteger(baseBN.toString());    const n = new BigInteger(moduloBN.toString());    const expected = baseBN.invm(moduloBN);    expect(a.modInv(n).toString()).to.equal(expected.toString());    expect(() => a.mul(n).modInv(n)).to.throw('Inverse does not exist');  });
  it('getBit is correct', async function() {    const i = 5;    const nBN = await getRandomBN(new BN(2), new BN(200));    const n = new BigInteger(nBN.toString());    const expected = nBN.testn(5) ? 1 : 0;    expect(n.getBit(i) === expected).to.be.true;  });});