We Keep Coding

Obtaining same Base64 encoded output of encrypted string in Java and JavaScript

After getting byte array encryptedMessageInBytes from AES encryption function call cipher.doFinal in Java, I convert the byte array to base64 like this:
String encryptedMessageInBase64 = new String(Base64.getEncoder().encode(encryptedMessageInBytes));
In JavaScript, I simply do .toString() to the output I get from CryptoJS.AES.encrypt method and I get exact same base64 string. i.e.
var encryptedMessageInBase64 = CryptoJS.AES.encrypt("Message", "Secret Passphrase").toString();
It gives same base64 string as in Java code.
However, in one of the Java source code, they have done like this:
String encryptedMessageInBase64 = Base64.getUrlEncoder().encodeToString(encryptedMessageInBytes);
What shall I do in JavaScript to obtain same base64 string?

Here is answer:
However, in one of the Java source code, they have done like this:
String encryptedMessageInBase64 = Base64.getUrlEncoder().encodeToString(encryptedMessageInBytes);*
Here, basically they have done UrlEncoding instead of Base64 encoding. It is nothing but replacing + and / characters with - and _ characters. Url encoding is when we want to send encoded string over HTTP where it treats these two as special characters this is why we need to replace them with some other characters which are HTTP friendly.

Encode in Java and Decode in Javascript

I want to pass a Base64 Image to the front end in a parameter.
I tried to send normal Base64 but it was giving me an error, probably because of the special characters in the Base64 Image.
So I tried in Java:
String base64Signature = Base64.getEncoder().encodeToString(image); // Encode to base64
return URLEncoder.encode(base64Signature, "utf-8"); // This class contains static methods for converting a String to the application/x-www-form-urlencoded MIMEformat
And in Javascript data.Signature has the image data. Neither
vm.Signature = data.Signature;
or
vm.Signature = decodeURIComponent(data.Signature);
worked. I copied the image data String in a online converter and it didn't display anything.
How should I do this?

The problem could be that Java's URLEncoder encodes spaces as + signs and JavaScript's decoder expects spaces as %20s. You can try replacing the + signs, for example:
decodeURIComponent(data.Signature.replace(/\+/g, '%20'));

C# version of the javascript function btoa

I need to recode something from js to c# that utilises the btoa method in js on a string of unicode chars to convert them to base64. However, as far as I know the encoding used by javascrpt is different to all those available in c#. I need the encoding to be exactly the same and not return different values across these languages. I have tried setting up a nodejs server and making get requests to it, in order to run the encoding that way, but this is far too slow and unstable. I am under the impression I would need to make my own encoding table but I have no idea where to start or how to implement this. If anyone could help that would be greatly appreciated.
tl;dr: javascript's btoa returns different value than base 64 encoding in c# does. I need it to be the same values.
code and outputs:
c#:
String fromChar = new
String(247,71,186,8,125,72,2,1.0078125,0.003936767578125);
var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(fromChar);
Console.WriteLine(System.Convert.ToBase64String(plainTextBytes));
output = w7dHwroIfUgCAQA=
javascript:
var x = btoa(String.fromCharCode(247,71,186,8,125,72,2,1.0078125,0.003936767578125);
console.log(x)
output =
90e6CH1IAgEA
I am aware the former example uses utf8 encoding which js does not, the problem is there is no encoding in .net that matches the javascript encoding.
Edit: Tried to compare the byte arrays of both c# and javascript but the problem is the btoa function uses an unnamed encoding, so I can't actually get the bytes to print the byte array for it without assuming it is something like utf8 which it is not.

Worked it out. For anyone wondering the encoding used is iso encoding. The btoa function in javascript can be replicated by using the following c# method:
public string encoding(string toEncode)
{
byte[] bytes= Encoding.GetEncoding(28591).GetBytes(toEncode);
string toReturn = System.Convert.ToBase64String(bytes);
return toReturn;
}

The decoding will be the following:
string base64EncodedString = "6Q==";
Encoding.GetEncoding(28591).GetString(Convert.FromBase64String(base64EncodedString));
// "é"

Getting MD5 hash in JavaScript and converting it to base 64

I’d like to use a set of REST API through JavaScript and I’m reading the documentation explaining how to implement authentication.
The following instructions are illustrated in pseudocode but I have some issue on understanding how to implement it in JavaScript (my JS level is quite basic).
This is the unclear part:
= FromBytesToBase64String(MD5Hash("{\n \"data\": {\n \"type\": \"company\",\n \"id\": \"879f2dfc-57ea-4dbb-96c7-c546f8812f1e\",\n \"external_1_value\": \"Updated value\"\n }\n}"))
Basically I should calculate MD5 hash of the string in question and then I should encode it in base 64 string If I understood well.
The documentation shows the flow broken in sub-steps:
= FromBytesToBase64String(b'eC\xcda\xa3\xa7\xaf\xa53\x93\xb4.\xa2\xb1\xe3]')
And then the final result:
"ZUPNYaOnr6Uzk7QuorHjXQ=="
I tried to do the same by using crypto.js library and I get a MD5 hash string but then how can I get this value "ZUPNYaOnr6Uzk7QuorHjXQ==" ?
Any idea on how I could do it?
Thanks so much for helping!

That final result is the base64 encoded string. The function FromBytesToBase64String is what produces it, but this is not a standard function in JavaScript.
Instead, try using one of the built-in functions documented here. Specifically:
window.btoa(MD5Hash("Your input string"));

window.btoa(MD5Hash("Your input string")); does not work because btoa takes the md5 string and converts that character by character, hence you need to feed it an byte array.I ended up combining ArrayBuffer to base64 encoded string
with https://github.com/pvorb/node-md5/issues/25
into :
function md5ToBase64(md5String,boolTrimLast){
var strRet = arrayBufferToBase64(hexByteStringToByteArray(md5String));
return boolTrimLast?strRet.slice(0,22):strRet;
}

use the btoa() function to get a base64 encoded string.

Use WindowBase64.btoa():
var encodedData = window.btoa(md5Hash);

Detect whether JavasScript string has been encoded using encodeURIComponent

I'm working to integrate some code with a third party, and sometimes a string argument they pass to a Javascript function I'm writing will be encoded using encodeURIComponent, sometimes it won't be.
Is there a definitive way to check whether it's been encoded using encodeURIComponent
If not, I'll do the encoding then

You could decode it and see if the string is still the same
decodeURIComponent(string) === string

Not reliably, especially in the case where a string may be encoded twice:
encodeURIComponent('http://stackoverflow.com/')
// yields 'http%3A%2F%2Fstackoverflow.com%2F'
encodeURIComponent(encodeURIComponent('http://stackoverflow.com/'))
// yields 'http%253A%252F%252Fstackoverflow.com%252F'
In essence, if you were to try and detect the string encoding when the passed argument is not actually encoded but has qualities of an encoded string, you'd be decoding something you shouldn't.
I'd recommend adding a second parameter in the definition "isURIComponent".
However, if you wanted to attempt, perhaps the following would do the trick:
if ( str.match(/[_\.!~*'()-]/) && str.match(/%[0-9a-f]{2}/i) ) {
// probably encoded with encodeURIComponent
}
This tests that the non alphanumeric characters that don't get encoded are intact, and that hexadecimals exist (e.g. %20 for a space)