enc_mods.aes.java Source code

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Here is the source code for enc_mods.aes.java

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package enc_mods;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import sec_algo.*;
import java.io.UnsupportedEncodingException;
import java.security.KeyFactory;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;

/**
 *
 * @author Marienne Lopez
 * @source aesencryption.net - Java AES encryption example
 */
public class aes {

    private static final int AES_Key_Size = 256;
    private byte[] key;

    private SecretKeySpec secretkey;
    private Cipher cipher;

    public void setKey() {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(AES_Key_Size);
            SecretKey aeskey = kgen.generateKey();
            key = aeskey.getEncoded();
            secretkey = new SecretKeySpec(key, "AES");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public Cipher getCipher() {
        return this.cipher;
    }

    public SecretKeySpec getKey() {
        return this.secretkey;
    }

    public void saveKey(String fileloc) {
        File output = new File(fileloc);
        //save key to file
    }

    public String getDecryptedString(String str) {
        String decrypted = "";
        try {
            cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, secretkey);
            decrypted = new String(cipher.doFinal(Base64.decodeBase64(str)));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return decrypted;
    }

    public String getEncryptedString(String str) {
        String encrypted = "";
        if (secretkey == null) {
            System.out.println("no key");
        } else {
            try {
                cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
                cipher.init(Cipher.ENCRYPT_MODE, secretkey);
                encrypted = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return encrypted;
    }

    /**
    * Decrypts an AES key from a file using an RSA private key
    */
    public void loadKey(File in, File privateKeyFile) {
        try {
            // read private key to be used to decrypt the AES key
            byte[] encodedKey = new byte[(int) privateKeyFile.length()];
            new FileInputStream(privateKeyFile).read(encodedKey);

            // create private key
            PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(encodedKey);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            PrivateKey pk = kf.generatePrivate(privateKeySpec);

            // read AES key
            cipher.init(Cipher.DECRYPT_MODE, pk);
            key = new byte[AES_Key_Size / 8];
            CipherInputStream is = new CipherInputStream(new FileInputStream(in), cipher);
            is.read(key);
            secretkey = new SecretKeySpec(key, "AES");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Encrypts the AES key to a file using an RSA public key
     */
    public void saveKey(File out, File publicKeyFile) {
        try {
            // read public key to be used to encrypt the AES key
            byte[] encodedKey = new byte[(int) publicKeyFile.length()];
            new FileInputStream(publicKeyFile).read(encodedKey);

            // create public key
            X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(encodedKey);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            PublicKey pk = kf.generatePublic(publicKeySpec);

            // write AES key
            cipher.init(Cipher.ENCRYPT_MODE, pk);
            CipherOutputStream os = new CipherOutputStream(new FileOutputStream(out), cipher);
            os.write(key);
            os.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}