SOURCE

//Crypto.js
function base64Decode(text) { return CryptoJS.enc.Utf8.stringify(CryptoJS.enc.Base64.parse(text)) }
function testDecode(url) {
    try{
        var str = url.match(/(\w+(bTN1OA|Lm0zdTg|eC5tM3U4))/)[1];
        var result = base64Decode(str);
        console.log(result);
    }catch(e){
    }
}

testDecode('aHR0cHM6Ly90Ny5jZG4yMDIwLmNvbS92aWRlby9tM3U4LzIwMjEvMDYvMjEvYjNiMGIyMzAvaW5kZXgubTN1OA1234512345');
testDecode('aHR0cHM6Ly90Ny5jZG4yMDIwLmNvbS92aWRlby9tM3U4LzIwMjEvMDYvMjEvYjNiMGIyMzAvaW5kZXgubTN1OA12345');
testDecode('aHR0cHM6Ly92aXAzLmxiYmY5LmNvbS8yMDIzMDQyNS9lSmdXc1FvYS9pbmRleC5tM3U4');
testDecode('aHR0cHM6Ly92aXAzLmJmYmZoYW8uY29tLzIwMjMwNDA4L0diOVVXTDB4L2luZGV4Lm0zdTgO0O0O');
testDecode('aHR0cHM6Ly92aXAzLmJmYmZoYW8uY29tLzIwMjMwNDA4L0diOVVXTDB4L2luZGV4Lm0zdTgO0O0OO0O0O');