Develop Reference

Change segment text before processing using hls.js

so due to some security reason i want to add some extra text to .ts file in the begining of so when parsing it causes buffering issues
to fix this i decided to removed that 'extra' text i added before processing the segment issue is i dont know how to manipulate arraybuffer so i can remove that text since i am not that knowledgable on js
I tried many things including just download hlsjs file directly then edit readystatechange
// >= HEADERS_RECEIVED
if (readyState >= 2) {
....
if (isArrayBuffer)
{
console.log(xhr.response);
var ress = xhr.response;
//console.log(ress.replace('FFmpeg',''));
var enc = new TextDecoder('ASCII');
var seg = enc.decode(ress);
//var binaryArray = new Uint8Array(this.response.slice(0)); // use UInt8Array for binary
//var blob = new Blob([seg], { type: "video/MP2T" });
var enc = new TextEncoder(); // always utf-8
var newww = enc.encode(enc.encode(seg));
var ddd = newww.buffer;
console.debug( newww );
console.debug( newww.buffer);
//dec = dec.replace('ÿØÿà �JFIF','') ;
//xhr.response = Array.from(newww) ;
data = ddd;
len = data.byteLength;
the idea was to convert arraybuffer to string remove that text then convert it back to arraybuffer

TripleDES Java Encryprion to Javascript Decryption

I am using Java to encrypt a text payload with Triple DES. First I create an ephemeral key that I will use for encrypting the payload:
private byte[] createEphemeralKey() throws Exception {
KeyGenerator keygen = KeyGenerator.getInstance("DESede");
keygen.init(168);
return keygen.generateKey().getEncoded();
}
Then I encrypt my payload with said key:
private String encryptTripleDES(byte[] ephemeralKey, String payload) throws Exception {
Cipher cipher = Cipher.getInstance("DESede/ECB/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(ephemeralKey, "DESede"));
byte[] plainTextBytes = payload.getBytes();
byte[] cipherText = cipher.doFinal(plainTextBytes);
return Base64.getEncoder().encodeToString(cipherText);
}
Also need a padding function to ensure the data length is divisable by 8:
private String adjustPadding(String input, int blockSize) {
int len = input.length() % blockSize;
int paddingLength = (len == 0) ? 0 : (blockSize - len);
while (paddingLength > 0) {
input += "F";
paddingLength--;
}
return input;
}
And here is my process end to end:
String data = "Marnus"
byte[] = ephemeralKey = createEphemeralKey();
String adjustedData = adjustPadding (data,8);
String encryptedPayload = encryptTripleDES(ephemeralKey, adjustedData);
String encodedKey = Base64.getEncoder().encodeToString(ephemeralKey)
So I take the 2 variables encryptedPayload and encodedKey, that are both Base64 encoded string, and send it off via HTTP to node express app.
In the Javascript side of things, I use node-forge - Here is the part of my express app that does the decryption:
let nodeBuffer = Buffer.from(data, 'base64')
let input = forge.util.createBuffer(nodeBuffer.toString('binary'))
// 3DES key and IV sizes
let keySize = 24;
let ivSize = 8;
let derivedBytes = forge.pbe.opensslDeriveBytes(ephemeralKey, null, keySize + ivSize);
let buffer = forge.util.createBuffer(derivedBytes);
let key = buffer.getBytes(keySize)
let iv = buffer.getBytes(ivSize)
let decipher = forge.cipher.createDecipher('3DES-ECB', key)
decipher.start({iv: iv})
decipher.update(input)
console.log('decipher result', decipher.finish())
let decryptedResult = decipher.output.data;
Here is an Triples DES example in the node-forge docs:
A few notes:
I create a node-forge buffer from a regular buffer since I don't have a input file like the examples gives. Here is how the docs states one should create one buffer from the other:
*I use base64 as that is what I used in the java side to encode the data that was sent.
Then, I dont have a salt so I left the 2'nd param null in opensslDeriveBytes as specified in the docs I should do.
Thirdly, I am also not sure if my keysize of 24 is correct?
My results
So doing an end to end test yields the following:
In my Java app, the test data was "Marnus", the encryptedPayload was ez+RweSAd+4= and the encodedKey was vCD9mBnWHPEBiQ0BGv7gc6GUCOoBgLCu.
Then in my javascript code data was obviously ez+RweSAd+4=(encryptedPayload) and the ephemeralKey was vCD9mBnWHPEBiQ0BGv7gc6GUCOoBgLCu(encodedKey).
After the decryption ran, the value of decryptedResult was ©ýÕ?µ{', which is obviously just garbage since it was not encoded yet, but I cant figure out which encoding to use?
I tried using forge.util.encode64(decipher.output.data), but that just gave me qf3VP7UYeyc=, which is not right.
For what it's worth, here is the type that decipher.output

With a lot more tweaking and testing different options, I got it working - and the good news is I managed to get it all working with the built in crypto library in nodejs (v12.18.4).
First things first, the JAVA side just needs a change to the key size (from 168 to 112), the rest remains the same - see below example as one single method (should be split up in final implementation of course for testability and usability):
//Some data:
String payload = "{\"data\":\"somedata\"}";
// Create Key
KeyGenerator keygen = KeyGenerator.getInstance("DESede");
keygen.init(112);
byte[] ephemeralKey = keygen.generateKey().getEncoded();
// Adjust the data, see adjustPadding method in the question for details.
String data = adjustPadding (payload,8);
// Wil now be "{"data":"somedata"}FFFFF", can just chop off extra in JS if need be. When sending JSON one knows the end of the object will always be "}"
// Do Encrypt
Cipher cipher = Cipher.getInstance("DESede/ECB/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(ephemeralKey, "DESede"));
byte[] plainTextBytes = data.getBytes();
byte[] cipherText = cipher.doFinal(plainTextBytes);
String encryptedPayload = Base64.getEncoder().encodeToString(cipherText);
//Lastly, Base64 the key so you can transport it too
String encodedKey = Base64.getEncoder().encodeToString(ephemeralKey)
on the Javascript side of things we keep it simple:
// I'm using TS, so change the import if you do plain JS
import crypto = require('crypto')
//need bytes from the base64 payload
let buff = Buffer.from(ephemeralKey, 'base64')
const decipher = crypto.createDecipheriv('des-ede3', buff, null)
decipher.setAutoPadding(false)
let decrypted = decipher.update(data, 'base64', 'utf8')
decrypted += decipher.final('utf8')
console.log(decrypted)
//{"data":"somedata"}FFFFF"

Exception when converting to image from Base-64 string

I am trying to send a Highcharts chart via image on ASP.NET button click.
What I am trying to do is:
Convert the chart to base64 image, the code is the following :
var chart = $('#main-content').highcharts();
EXPORT_WIDTH = 1000;
var render_width = EXPORT_WIDTH;
var render_height = render_width * chart.chartHeight / chart.chartWidth;
var svg = chart.getSVG({
exporting: {
sourceWidth: chart.chartWidth,
sourceHeight: chart.chartHeight
}
});
var contentToSend = 'data:image/svg+xml;base64,' + window.btoa(svg);
var hdnField = document.getElementById("MainContent_ChartImage");
hdnField.value = contentToSend;
Next step is taking the base64 image value, convert it to image an attach it to the mail, the code is:
string textImage = ChartImage.Value;
var imageData = Convert.FromBase64String(HttpUtility.UrlDecode(data));
System.Net.Mail.LinkedResource res;
AlternateView htmlView;
using (MemoryStream ms = new MemoryStream(imageData, true))
{
ms.Position = 0;
ms.Write(imageData, 0, imageData.Length);
ms.Seek(0, SeekOrigin.Begin);
res = new System.Net.Mail.LinkedResource(ms);
htmlView = AlternateView.CreateAlternateViewFromString("<html><body><img src='cid:imageReport' width='100%' ></body></html>", null, "text/html");
res.ContentId = "imageReport";
htmlView.LinkedResources.Add(res);
MailMessage mailMsg = new MailMessage();
SmtpClient client = new SmtpClient();
// ...
mailMsg.IsBodyHtml = true;
mailMsg.AlternateViews.Add(htmlView);
client.Send(mailMsg);
}
but the method Convert.FromBase64String throws an exception
{"The input is not a valid Base-64 string as it contains a non-base 64
character, more than two padding characters, or an illegal character
among the padding characters. "}
However when I remove 'data:image/svg+xml;base64,' then convert it, it doesn't throw an exception but the image will not appear. What should I do?
Thank you

Get rid of the beginning part of the string: "data:image/svg+xml;base64," that part is not base64, just the remainder is. You don't need to use HttpUtility.UrlDecode either.
You should specify the TransferEncoding as Base64:
res.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
However with all that said, there are some strong caveats to using SVG in email. So you may want to consider a different format such as JPG or PNG. If that's the route you take, you will need to use a library to convert formats.

After many researches I found the solution , the main problem was that not all client email support data URI :
What is Data URI support like in major email client software?
i was trying to open the mail from the outlook 2016 however it is not supported , when i opened from hotmail.com it worked..
the code is :
MailMessage mailMsg = new MailMessage();
SmtpClient client = new SmtpClient();
var imageData = Convert.FromBase64String(data);
var contentId = Guid.NewGuid().ToString();
var linkedResource = new LinkedResource(new MemoryStream(imageData), "image/svg+xml");
linkedResource.ContentId = contentId;
linkedResource.TransferEncoding = TransferEncoding.Base64;
var body = string.Format("<img src=\"cid:{0}\" />", contentId);
var htmlView = AlternateView.CreateAlternateViewFromString(body, null, "text/html");
htmlView.LinkedResources.Add(linkedResource);
mailMsg.AlternateViews.Add(htmlView);

VBA for Excel, how to load a .js file as Jscript Scriptcontrol object

I know it's a bit silly to load a js into VBA, but I need to load the libphonenumber library by Google to perform an analysis of a big bunch of phone numbers.
I tried to adapt the following code borrowed from here, but the compiled library is to big to be inserted into the Vba code.
Is there any way to load the .js library from a file instead?
Thanks!
Function encodeURL(str As String)
Dim ScriptEngine As ScriptControl
Set ScriptEngine = New ScriptControl
ScriptEngine.Language = "JScript"
ScriptEngine.AddCode "function encode(str) {return encodeURIComponent(str);}"
Dim encoded As String
encoded = ScriptEngine.Run("encode", str)
encodeURL = encoded
End Function
UPDATE.
This should be a working code, but for some reason doesn't works:
Function loabdjs(x As String)
Dim fso As Scripting.FileSystemObject
Set fso = New Scripting.FileSystemObject
Dim script As String
Dim fs As Scripting.TextStream
''' CODE : "function encode(str) {return encodeURIComponent(str);}"
Set fs = fso.OpenTextFile("test.js", ForReading, False)
MsgBox ("Never reached this point")
script = fs.ReadAll
fs.Close
Dim ScriptEngine As ScriptControl
Set ScriptEngine = New ScriptControl
Dim output As String
ScriptEngine.Language = "JScript"
ScriptEngine.AddCode script
output = ScriptEngine.Run("encode", x)
loadjs = output
End Function
Any ideas?

Read the library from the filesystem into a string:
Dim fso As Scripting.FileSystemObject
Set fso = New Scripting.FileSystemObject
Dim fs As Scripting.TextStream
Set fs = fso.OpenTextFile( "libphonenumber.js", ForReading, False )
Dim script As String
script = fs.ReadAll
fs.Close()
scriptEngine.AddCode script

may be this:
Function loabdjs(x As String)
...
...
loadjs = output
End Function

I know this question is old but for anyone looking for an answer, this is a working example
Sub loadFile()
Const ForReading = 1, ForWriting = 2, ForAppending = 8
Const TristateUseDefault = -2, TristateTrue = -1, TristateFalse = 0
Dim fs, f, ts, script
Set fs = CreateObject("Scripting.FileSystemObject")
Set f = fs.GetFile("C:\test.js")
Set ts = f.OpenAsTextStream(ForReading, TristateUseDefault)
script = ts.ReadAll
Debug.Print script
ts.Close
End Sub

Scrape webpage that requires md5 hash as a parameter

I am trying to scrape the data from the below link, in a c# console app:
https://www.eex-transparency.com/homepage/power/germany/production/availability/non-usability
Using the developer tools in chrome I can see that its possible to get a json response, the url to get this is:
https://www.eex-transparency.com/dsp/tem-12?country=de&expires=1454345128&md5=TRhtJei_go4ueLeekBc8yw
the website uses this js file (https://www.eex-transparency.com/assets/js/tpe-website.js) to generate the expires and md5 hash key. I think I've figured out that the expires value is a unix datetime. I have never used javascript before so finding it hard to figure out how they construct the md5.
The Javascript that generates these code is:
generateCryptedParams=function(url,clientIP)
{
var cryptedParams,md5,md5Encoded,md5WithoutSpeciaChars,parser,timePoint,urlPath;
return timePoint=moment().tz("Europe/Berlin").add(1,"minute").unix(),
parser=document.createElement("a"),
parser.href=url,
urlPath=parser.pathname,
"/"!==urlPath[0]&&(urlPath="/"+urlPath),
md5=CryptoJS.MD5(urlPath+timePoint+clientIP+" zYeHzBomGdgV"),
md5Encoded=md5.toString(CryptoJS.enc.Base64),
md5WithoutSpeciaChars=replaceSpecialChars(md5Encoded),
cryptedParams={"expires":timePoint,"md5":md5WithoutSpeciaChars}
}
replaceSpecialChars=function(str)
{
var key,specialChars,value;
specialChars={"=":"","\\+":"-","/":"_","%":"_"};
for(key in specialChars)
value=specialChars[key],
str=str.replace(new RegExp(key,"g"),value);
return str
}
As i said I think I'm comfortable with the timepoint part but the md5 is confusing me. Below is my C# code to replicate their but when I pass the md5 hash their site returns a 403 Forbidden error.
public Tuple<string, Int32> GenerateCrypto(string url, string ipAddress)
{
string cetId = "Central European Standard Time";
TimeZoneInfo cetZone = TimeZoneInfo.FindSystemTimeZoneById(cetId);
var CETDateTime = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, cetZone);
//Int32 unixTimestamp = (Int32)(CETDateTime.Subtract(new DateTime(1970, 1, 1))).TotalSeconds;
Int32 unixTimestamp = (Int32)(DateTime.UtcNow.AddMinutes(1).Subtract(new DateTime(1970, 1, 1))).TotalSeconds;
url = url.Split('/')[3];
var md5 = CipherUtility.GenerateMd5(url + unixTimestamp + ipAddress + " zYeHzBomGdgV");
var md5Encoded = Convert.ToBase64String(Encoding.UTF8.GetBytes(md5));
var md5withoutSpecialCharts = replaceSpecialChars(md5Encoded);
md5withoutSpecialCharts = md5withoutSpecialCharts.Substring(0, 22);
return new Tuple<string, Int32>(md5withoutSpecialCharts, unixTimestamp);
}

The solution was that I needed to concatenate a const string to all the elements before hashing it.