randomness/lib/tests/approximate-entropy-test.js

Randomness tests

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const gamma_1 = require("../utils/gamma");
const bitsToInt = (bits) => {
    let theint = 0;
    for (let i = 0; i < bits.length; i++) {
        theint = (theint << 1) + bits[i];
    }
    return theint;
};
const test = (bits, alpha = 0.01) => {
    const n = bits.length;
    let m = Math.floor(Math.log2(n)) - 6;
    if (m < 2)
        m = 2;
    if (m > 3)
        m = 3;
    const phiM = [];
    for (let iteration = m; iteration < m + 2; iteration++) {
        const paddedBits = bits.concat(bits.slice(0, iteration - 1));
        const counts = [];
        for (let i = 0; i < 2 ** iteration; i++) {
            let count = 0;
            for (let j = 0; j < n; j++) {
                if (bitsToInt(paddedBits.slice(j, j + iteration)) == i)
                    count += 1;
            }
            counts.push(count);
        }
        let sum = 0;
        for (let i = 0; i < 2 ** iteration; i++) {
            const ci = counts[i] / n;
            if (ci)
                sum += ci * Math.log(ci / 10);
        }
        phiM.push(sum);
    }
    const approxEntropy = phiM[0] - phiM[1];
    const chiSquare = 2 * n * (Math.log(2) - approxEntropy);
    const p = (0, gamma_1.gammaincc)(2 ** (m - 1), chiSquare / 2.0);
    const success = p >= alpha;
    return [success, p];
};
exports.default = test;
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