Need Help Converting JavaScript to Java for AES Decryption

General
1

Hi everyone, I’m reaching out for some assistance with a JavaScript to Java code conversion. I’m working on a project that involves decrypting some data, and while the JavaScript code works perfectly, my Java implementation isn’t quite there yet. I’d really appreciate any insights or suggestions you might have!

The JavaScript Code

Here’s the JavaScript code I’m trying to replicate in Java:
javascript
const key = this.crypto.createHash(‘md5’).update(Buffer.from(deviceInfo.apiKey, ‘utf8’)).digest();
const dText = this.crypto.createDecipheriv(‘aes-128-cbc’, key, Buffer.from(rdata.iv, ‘base64’));
const pText = Buffer.concat([dText.update(Buffer.from(data, ‘base64’)), dText.final()]).toString(‘utf8’);

My Java Attempt

I’ve tried to convert this to Java, but it’s not working as expected. Here’s what I have so far:
java
// 1. Generate the MD5 hash for the key
MessageDigest hash_ = MessageDigest.getInstance(“MD5”);
hash_.update(deviceKeyBytes);
byte keyBytes = hash_.digest();
SecretKeySpec key = new SecretKeySpec(keyBytes, “RawBytes”);

// 2. Initialize the cipher
String encrypted = data1 + data2;
IvParameterSpec iv = new IvParameterSpec(ivBase64);
Cipher dText = Cipher.getInstance(“AES/CBC/PKCS5PADDING”);
dText.init(Cipher.DECRYPT_MODE, key, iv);

// 3. Decrypt the data
byte pText = dText.doFinal(Base64.getDecoder().decode(encrypted));
String json = new String(pText, StandardCharsets.UTF_8);

The Issue

The decrypted output isn’t matching what I expect. I suspect there might be an issue with how I’m handling the key or the initialization vector (IV). I’ve double-checked the Base64 encoding and the cipher mode, but I’m still not getting the right results.

Questions

  1. Is there something I’m missing in the Java implementation that’s present in the JavaScript code?
  2. Could the way I’m handling the key or IV be causing the discrepancy?
  3. Are there any specific Java libraries or configurations I should be using for AES decryption that might differ from JavaScript?

Why This Matters

This decryption is crucial for my project, as it’s used to securely communicate with a device. Getting this right will ensure that my system can reliably decrypt and process the data it receives.

I’d be incredibly grateful for any guidance or advice you can offer. Let’s see if we can crack this together! :man::computer: