Java BouncyCastle ECDSA sect233r1 signing

Main.java

import java.io.IOException;
import java.math.BigInteger;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.*;
import java.security.spec.ECPrivateKeySpec;
import java.security.spec.InvalidKeySpecException;
 
import org.bouncycastle.jce.ECNamedCurveTable;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECParameterSpec;
 
public class Main {
 
    /*
        1) copy ctcert.bin into the ctcert section of the footer
        2) hash the hashes in footer.bin
        3) use the private key in ctcert.bin to sign the hash of the hashes (use bouncycastle for this??)
        4) place the newly generated signature in the correct spot
     */
 
    public static void main(String[] args) {
        try {
            DoSigning();
        } catch (IOException | InvalidAlgorithmParameterException | NoSuchProviderException | NoSuchAlgorithmException | InvalidKeyException | SignatureException | InvalidKeySpecException e) {
            System.out.println(e.getMessage());
            System.exit(-1);
        }
    }
 
    private static void DoSigning() throws IOException, InvalidAlgorithmParameterException, NoSuchProviderException, NoSuchAlgorithmException, InvalidKeyException, SignatureException, InvalidKeySpecException {
        byte [] footer = Files.readAllBytes(Paths.get("C:\\Users\\jason\\Desktop\\cryptor\\footer.bin"));
        byte [] ctcert_bin = Files.readAllBytes(Paths.get("C:\\Users\\jason\\Desktop\\cryptor\\ctcert.bin"));
 
        byte[] public_key = new byte[0x3C];
        System.arraycopy(ctcert_bin, 0x108, public_key, 0, 0x3C);
 
        byte[] privkey = new byte[0x1E];
        for (int i = 0; i < 0x1E; i++)
            privkey[i] = ctcert_bin[0x180 + 0x1E - 1 - i];
        BigInteger private_key = new BigInteger(privkey);
 
        byte[] hashes = new byte[14*0x20];
        System.arraycopy(footer, 0, hashes, 0, 14*0x20);
        MessageDigest md = null; try { md = MessageDigest.getInstance("SHA-256"); } catch (Exception e) {}
        byte[] hash_of_hashes = md.digest(hashes);
 
        System.out.print("The hash of the hashes --> ");
        for (byte b : hash_of_hashes) System.out.printf("%X", b);
        System.out.println();
 
        //======== ECDSA CODE =======
 
        Security.addProvider(new BouncyCastleProvider());
 
        ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("sect233r1");
        KeyFactory factory = KeyFactory.getInstance("ECDSA", "BC");
 
        ECParameterSpec params = new ECParameterSpec();
        ECPrivateKeySpec spec = new ECPrivateKeySpec(private_key, params);
        PrivateKey privKey = factory.generatePrivate(spec);
 
        System.out.println(privKey.toString());
 
        Signature ecdsaSign = Signature.getInstance("SHA256withECDSA", "BC");
        ecdsaSign.initSign(privKey);
        ecdsaSign.update(hash_of_hashes);
        byte[] signature = ecdsaSign.sign();
 
        System.out.print("The signature of the hash of the hashes --> ");
        for (byte b : signature) System.out.printf("%X", b);
        System.out.println();
    }
}