integrated totp (nodejs)

test-totp.js

const {fn: {b32_buf, buf_b32, getOTP}} = require('./totp')
const givea = fuck => console.log('%s %j', fuck.length.toString().padStart(4), fuck.toString())

const it = process.hrtime()
const rt = ([s,ns] = process.hrtime(it)) => console.log('%ss elapsed', (s+ns/1e9).toFixed(9).padStart(12))

rt()
const fucks = Buffer.from('Hi there fucks')
givea(fucks)

rt()
const b32fucks = buf_b32(fucks)
givea(b32fucks)

rt()
const ofucks = b32_buf(b32fucks)
givea(ofucks)
console.assert(ofucks.equals(fucks))

rt()
const ok = Buffer.from([0x3d])
givea(ok)

rt()
const bok = buf_b32(ok)
givea(bok)

rt()
const b32ok = b32_buf(bok)
givea(b32ok)

console.assert(b32ok.equals(ok))

rt()
const crap = getOTP(fucks)
givea(crap)

rt()
const shit = getOTP(fucks)
givea(shit)

setTimeout(()=>{rt(); givea(getOTP(fucks)); rt()}, 3e4)

test.log

 0.000192332s elapsed
  14 "Hi there fucks"
 0.005373599s elapsed
  24 "JBUSA5DIMVZGKIDGOVRWW4Y="
 0.006357218s elapsed
  14 "Hi there fucks"
 0.007532192s elapsed
   1 "="
 0.008020879s elapsed
   8 "HU======"
 0.008177638s elapsed
   1 "="
 0.008350557s elapsed
   6 "122610"
 0.009628935s elapsed
   6 "122610"
30.043018793s elapsed
   6 "465683"
30.044405246s elapsed

totp.js

const crypto = require('crypto')
const {b32c, b256} = Array.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ234567').reduce((o,c,i)=>{
	o.b32c[c] = i;
	o.b32c[c.codePointAt(0)] = i;
	o.b256[i] = c.codePointAt(0);
	return o;
}, {b32c: Object.create(null), b256: Buffer.alloc(33)})
// console.log(b32c, c32b)


const _31 = Math.pow(2,31)-1 // shorthand to fill crap
const b32_buf = b32 => {
	let B32 = b32
	let ec = B32.indexOf('=') > -1 ? B32.length - B32.indexOf('=') : 0
	let v1, v2, v3, v4, v5, v6, v7, v8, 
		buf = Buffer.allocUnsafe(Math.abs(5 * Math.ceil(B32.length / 8) - ec)),
		i = 0,
		idx = 0,
		len = b32.indexOf('='),
		cnt = len >> 3 << 3,
		rem = len - cnt

	// 8 chars are 5 bytes
	while (i < cnt) {
		v1 = b32c[B32[i++]];
		v2 = b32c[B32[i++]];
		v3 = b32c[B32[i++]];
		v4 = b32c[B32[i++]];
		v5 = b32c[B32[i++]];
		v6 = b32c[B32[i++]];
		v7 = b32c[B32[i++]];
		v8 = b32c[B32[i++]];

		buf[idx++] = (v1 << 3 | v2 >>> 2) & 255;
		buf[idx++] = (v2 << 6 | v3 << 1 | v4 >>> 4) & 255;
		buf[idx++] = (v4 << 4 | v5 >>> 1) & 255;
		buf[idx++] = (v5 << 7 | v6 << 2 | v7 >>> 3) & 255;
		buf[idx++] = (v7 << 5 | v8) & 255;
	};
	switch (rem) {
		case 2:
			v1 = b32c[B32[i++]];
			v2 = b32c[B32[i++]];

			buf[idx++] = (v1 << 3 | v2 >>> 2) & 255;
			break;
		case 4:
			v1 = b32c[B32[i++]];
			v2 = b32c[B32[i++]];
			v3 = b32c[B32[i++]];
			v4 = b32c[B32[i++]];

			buf[idx++] = (v1 << 3 | v2 >>> 2) & 255;
			buf[idx++] = (v2 << 6 | v3 << 1 | v4 >>> 4) & 255;
			break;
		case 5:
			v1 = b32c[B32[i++]];
			v2 = b32c[B32[i++]];
			v3 = b32c[B32[i++]];
			v4 = b32c[B32[i++]];
			v5 = b32c[B32[i++]];

			buf[idx++] = (v1 << 3 | v2 >>> 2) & 255;
			buf[idx++] = (v2 << 6 | v3 << 1 | v4 >>> 4) & 255;
			buf[idx++] = (v4 << 4 | v5 >>> 1) & 255;
			break;
		case 7:
			v1 = b32c[B32[i++]];
			v2 = b32c[B32[i++]];
			v3 = b32c[B32[i++]];
			v4 = b32c[B32[i++]];
			v5 = b32c[B32[i++]];
			v6 = b32c[B32[i++]];
			v7 = b32c[B32[i++]];

			buf[idx++] = (v1 << 3 | v2 >>> 2) & 255;
			buf[idx++] = (v2 << 6 | v3 << 1 | v4 >>> 4) & 255;
			buf[idx++] = (v4 << 4 | v5 >>> 1) & 255;
			buf[idx++] = (v5 << 7 | v6 << 2 | v7 >>> 3) & 255;
			break;
	};
	return buf;
};
const buf_b32 = buf => {
	let v1, v2, v3, v4, v5,
		b32 = Buffer.allocUnsafe(8 * Math.ceil(buf.length / 5)),
		i = 0,
		idx = 0,
		len = buf.length,
		cnt = Math.floor(len / 5) * 5,
		rem = len - cnt
	while (i < cnt) {
		v1 = buf[i++];
		v2 = buf[i++];
		v3 = buf[i++];
		v4 = buf[i++];
		v5 = buf[i++];

		b32.writeInt32BE(
			b256[v1 >>> 3] << 24
			| b256[(v1 << 2 | v2 >>> 6) & 31] << 16
			| b256[(v2 >>> 1) & 31] << 8
			| b256[(v2 << 4 | v3 >>> 4) & 31],
			4 * idx++
		);
		b32.writeInt32BE(
			b256[(v3 << 1 | v4 >>> 7) & 31] << 24
			| b256[(v4 >>> 2) & 31] << 16
			| b256[(v4 << 3 | v5 >>> 5) & 31] << 8
			| b256[v5 & 31],
			4 * idx++
		);
	};

	switch (rem) {
		case 1:
			v1 = buf[i++];

			b32.writeInt32BE(b256[v1 >>> 3] << 24 | b256[(v1 << 2) & 31] << 16 | 0x3d3d, 4 * idx++);
			b32.writeInt32BE(0x3d3d3d3d, 4 * idx++);
			break;
		case 2:
			v1 = buf[i++];
			v2 = buf[i++];

			b32.writeInt32BE(
				b256[v1 >>> 3] << 24
				| b256[(v1 << 2 | v2 >>> 6) & 31] << 16
				| b256[(v2 >>> 1) & 31] << 8
				| b256[(v2 << 4) & 31],
				4 * idx++
			);
			b32.writeInt32BE(0x3d3d3d3d, 4 * idx++);
			break;
		case 3:
			v1 = buf[i++];
			v2 = buf[i++];
			v3 = buf[i++];


			b32.writeInt32BE(
				b256[v1 >>> 3] << 24
				| b256[(v1 << 2 | v2 >>> 6) & 31] << 16
				| b256[(v2 >>> 1) & 31] << 8
				| b256[(v2 << 4 | v3 >>> 4) & 31],
				4 * idx++
			);
			b32.writeInt32BE(
				b256[(v3 << 1) & 31] << 24 | 0x3d3d3d,
				4 * idx++
			);
			break;
		case 4:
			v1 = buf[i++];
			v2 = buf[i++];
			v3 = buf[i++];
			v4 = buf[i++];

			b32.writeInt32BE(
				b256[v1 >>> 3] << 24
				| b256[(v1 << 2 | v2 >>> 6) & 31] << 16
				| b256[(v2 >>> 1) & 31] << 8
				| b256[(v2 << 4 | v3 >>> 4) & 31],
				4 * idx++
			);
			b32.writeInt32BE(
				b256[(v3 << 1 | v4 >>> 7) & 31] << 24
				| b256[(v4 >>> 2) & 31] << 16
				| b256[(v4 << 3) & 31] << 8
				| 0x3d,
				4 * idx++
			);
			break;
	};
	return b32;
};
const getOTP = (secret, len = 6, T0 = 0, TI = 30) => {
	const TC = Math.floor((Math.round(Date.now() / 1e3) - T0) / TI)
		.toString(16)
		.padStart(16, '0');

	const TOTP = crypto.createHmac('sha1', secret)
		.update(TC, 'hex')
		.digest()
		.readInt32BE(16) & _31;

	return String(TOTP % Math.pow(10, len)).padStart(6,'0');
};

const TOTP = {
	constants: {b32c, b256, _31},
	fn: {b32_buf, buf_b32, getOTP}
};
module.exports = TOTP;