decrypt.js

const cryptojs = require('crypto-js');
const abemafresh = [1413502068, 2104980084, 1144534056, 1967279194, 2051549272, 860632952, 1464353903, 1212380503];
const url = "abemafresh://abemafresh/206437t2806498f02ad88f4aecd7aa2083a6374edef/2928e09b0fa322020bbe5d854eb92984";
 
const part1 = url.split('/')[3];
const part2 = url.split('/')[4];
 
const hash = cryptojs.HmacSHA256(part1, cryptojs.lib.WordArray.create(abemafresh));
const decryptResult = cryptojs.AES.decrypt(cryptojs.lib.CipherParams.create({
    ciphertext: cryptojs.enc.Hex.parse(part2)
}), hash, {
        mode: cryptojs.mode.ECB,
        padding: cryptojs.pad.NoPadding
    }).toString();
 
for (var t = new Uint8Array(16), r = 0; 16 > r; r++)
    t[r] = parseInt(decryptResult.substr(2 * r, 2), 16);
 
const result = [];
 
for (const i of t) {
    result.push(i.toString(16).length === 1 ? ('0' + i.toString(16)) : i.toString(16));
}
 
console.log('key = ', result.join(''));