Solution for Flare-On 2019 Lvl 3 - Flarebear

FlareBearActivity.java

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.Charset;
import javax.crypto.*;
import java.security.*;
import java.security.spec.*;
import java.nio.file.Paths;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.*;
import java.io.IOException;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

 public final class FlareBearActivity {

 	public static final void main(String[] args) throws IOException {
 		System.out.println("Flare-On 2019: ");
 		String password = getPassword();
 		byte[] readBytes = Files.readAllBytes(Paths.get("ecstatic"));
 		byte[] readBytes2 = Files.readAllBytes(Paths.get("ecstatic2")); 
 		System.out.println("Ecstatic: "+readBytes.length);
 		System.out.println("Ecstatic2: "+readBytes2.length);
 		try {
 			byte[] decrypt = decrypt(password, readBytes);
            byte[] decrypt2 = decrypt(password, readBytes2);
            Files.write(Paths.get("ecstatic.decrypted"), decrypt, StandardOpenOption.CREATE);
            Files.write(Paths.get("ecstatic2.decrypted"), decrypt2, StandardOpenOption.CREATE);
 		}catch (Exception unused) {
 			System.out.println("Exception! "+unused);
        }
        System.out.println("Decrypted.");
 	}

 	public static final String getPassword() {
        return "flareflareflareflare*BEARBEARBEARBEARBEARBEARBEARBEAR+yeahyeah";
    }

    public static final byte[] decrypt(String str, byte[] bArr) throws NoSuchAlgorithmException, 
      InvalidKeySpecException, 
      NoSuchPaddingException, 
      InvalidKeyException, 
      IllegalBlockSizeException,
      InvalidAlgorithmParameterException,
      BadPaddingException {
    	Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
        String str2 = "UTF-8";
        Charset forName = Charset.forName(str2);
        String str3 = "Charset.forName(charsetName)";
        byte[] bytes = "pawsitive_vibes!".getBytes(forName);
        IvParameterSpec ivParameterSpec = new IvParameterSpec(bytes);
        char[] charArray = str.toCharArray();
        Charset forName2 = Charset.forName(str2);
        byte[] bytes2 = "NaClNaClNaCl".getBytes(forName2);
        SecretKey generateSecret = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1").generateSecret(new PBEKeySpec(charArray, bytes2, 1234, 256));
        SecretKeySpec secretKeySpec = new SecretKeySpec(generateSecret.getEncoded(), "AES");
        Cipher instance = Cipher.getInstance("AES/CBC/PKCS7Padding"); //AES/CBC/PKCS7Padding
        instance.init(2/*Cipher.DECRYPT_MODE*/, secretKeySpec, ivParameterSpec); //2
        byte[] doFinal = instance.doFinal(bArr);
        return doFinal;
    }
}