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package labb1säkerhet;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.UnrecoverableKeyException;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import javax.crypto.Cipher;

/**
 *
 * @author cong
 */
public class AES {

    static byte data[];

    static byte[] encKey1;
    static byte[] encIV;
    static byte[] encKey2;
    static byte[] ciphertext;
    static Key privateKey;
    static PublicKey publicKey;

    public static void main(String[] args) throws IOException, FileNotFoundException, KeyStoreException, NoSuchAlgorithmException, CertificateException, UnrecoverableKeyException, NoSuchProviderException, Exception {
        String filePath = "/home/cong/Skola/DT541C HT14 Trådlös kommunikation och säkerhet/DT541C HT14  datasäkerhet/Labb1/Lab _ Java Security Implementation/ciphertext.enc";

        // Create file object with the path
        File file = new File(filePath);
        // Assign the data from file to data[]
        data = readBytesFromFile(file);

        // Byte arrays
        encKey1 = new byte[128];
        encIV = new byte[128];
        encKey2 = new byte[128];
        ciphertext = new byte[1425];

        for (int i = 0; i < data.length; i++) {
            if (i < 128) {
                encKey1[i] = data[i];
            } else if (i >= 128 && i < 256) {
                encIV[i - 128] = data[i];
            } else if (i >= 255 && i < 383) {
                encKey2[i - 255] = data[i];
            } else if (i >= 383 && i < 1808) {
                ciphertext[i - 383] = data[i];
            }
        }

        for (int i = 0; i < encKey1.length; i++) {
            System.out.println(i + "=" + encKey1[i]);
        }
        System.out.println("");
        for (int i = 0; i < encIV.length; i++) {
            System.out.println(i + "=" + encIV[i]);
        }
        System.out.println("");
        for (int i = 0; i < encKey2.length; i++) {
            System.out.println(i + "=" + encKey2[i]);
        }

        getKeys();
        decryptKey();
    }

    public static byte[] readBytesFromFile(File file) throws IOException {
        InputStream is = new FileInputStream(file);

        // Get the size of the file
        long length = file.length();
        // You cannot create an array using a long type.
        // It needs to be an int type.
        // Before converting to an int type, check
        // to ensure that file is not larger than Integer.MAX_VALUE.
        if (length > Integer.MAX_VALUE) {
            throw new IOException("Could not completely read file " + file.getName() + " as it is too long (" + length + " bytes, max supported " + Integer.MAX_VALUE + ")");
        }

        // Create the byte array to hold the data
        byte[] bytes = new byte[(int) length];

        // Read in the bytes
        int offset = 0;
        int numRead = 0;
        while (offset < bytes.length && (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
            offset += numRead;
        }

        // Ensure all the bytes have been read in
        if (offset < bytes.length) {
            throw new IOException("Could not completely read file " + file.getName());
        }

        // Close the input stream and return bytes
        is.close();
        return bytes;
    }

    private static void getKeys() throws FileNotFoundException, KeyStoreException, IOException, NoSuchAlgorithmException, CertificateException, UnrecoverableKeyException {
        String labstorePass = "lab1StorePass";
        String password = "lab1KeyPass";
        String alias = "lab1EncKeys";
        String keystoreFilename = "/home/cong/Skola/DT541C HT14 Trådlös kommunikation och säkerhet/DT541C HT14  datasäkerhet/Labb1/Lab _ Java Security Implementation/lab1Store";
        FileInputStream is = new FileInputStream(keystoreFilename);

        KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
        keystore.load(is, labstorePass.toCharArray());

        Key key = keystore.getKey(alias, password.toCharArray());
        if (key instanceof PrivateKey) {
            // get certifcate of public key
            Certificate cert = keystore.getCertificate(alias);

            // get public key
            publicKey = cert.getPublicKey();

            // Return a key pair
            KeyPair keyPair = new KeyPair(publicKey, (PrivateKey) key);
            // Get private Key
            privateKey = keyPair.getPrivate();

        }

    }

    public static void decryptKey() {
        try {

            byte key1[] = new byte[128];
            byte key2[] = new byte[128];
            byte keyIV[] = new byte[128];
            Cipher rsaDec = Cipher.getInstance("RSA");
            rsaDec.init(Cipher.DECRYPT_MODE, privateKey);

            key1 = rsaDec.doFinal(encKey1);
            keyIV = rsaDec.doFinal(encIV);
            key2 = rsaDec.doFinal(encKey2);

            System.out.println("Key1 = " + new String(key1));
            System.out.println("KeyIV = " + new String(keyIV));
            System.out.println("key2 = " + new String(key2));

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}