如何使用非对称加密从另一个应用程序中的一个应用程序解密文本？

Question

我试图了解如何在一个已在单独的应用程序中加密的应用程序中解密字符串。我可以在单个应用程序执行中执行此操作，并且可以使用生成公钥的同一密钥对中的私钥。但是，我想在一个应用程序中加密该值，然后在另一个应用程序中解密该值。基本上，我有一个Web服务发送值，我不想被应用程序篡改，并且我打算使用非对称加密来处理它。随时让我知道我是否打算以错误的方式解决问题。

我尝试了多种加密技术，从对称开始。我遇到的问题是，每次都将值加密为相同的文本-如果我的目标是防止某人篡改值，这不是很有用-一旦他们知道某些文本的加密版本，他们将能够在任何请求中使用它。我一直在尝试遵循此处的标准-https://www.veracode.com/blog/research/encryption-and-decryption-java-cryptography 我可以让我的所有示例都在一个事务中执行加密/解密-只是当我尝试在一个请求中进行加密，然后在第二个请求中进行解密时，我失败了。

这是我当前的工作示例：

package com.ni.apps.cartencryptutil;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.xml.bind.DatatypeConverter;

import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;

/**
 * Security class for encrypting and decrypting Strings (that also works in WC ver 7 and above)
 *
 * @author 
 *
 */
public class SecurityTools {
  private static final Logger logger = Logger.getLogger(SecurityTools.class);

  private Cipher cipher;
  private IvParameterSpec initVector;
  private SecretKey secretKey;
  PrivateKey privateKeyParam;
  PublicKey publicKeyParam;
  private static SecureRandom secureRandom = new SecureRandom();

  private static final String TRANSFORMATION = "RSA/ECB/OAEPWithSHA-1AndMGF1Padding";
  private static final String ALGORITHM_SHORT = "RSA";
  private static final String RNG_ALGORITHM = "SHA1PRNG";
  private static final String ALGORITHM = "PBKDF2WithHmacSHA256";
  private static final String UTF8 = "UTF-8";

  // exceptions
  private static final String _ERR_ILLEGAL_BLOCK_SIZE = "illegal block size exception.";
  private static final String _ERR_BAD_PADDING = "bad padding exception.";
  private static final String _ERR_INVALIDKEY = "invalidkey exception.";
  private static final String _ERR_PADDING = "padding exception.";
  private static final String _ERR_NO_SUCH_ALGORITHM = "no such algorithm exception.";
  private static final String _ERR_PASSPHRASE_IS_NULL = "passphrase is null.";
  private static final String _ERR_INVALID_ALGORITHM = "invalid algorithm exception.";
  private static final String _ERR_UNSUPPORTED_ENCODING = "encoding not supported.";
  private static final String _ERR_INVALID_KEY_SPEC = "invalid key spec exception.";

  /**
   * Constructor
   *
   * @throws EncryptionException
   */
  public SecurityTools() throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering Constructor");
    }
    try {
      cipher = Cipher.getInstance(ALGORITHM_SHORT);
      generateIV();
      generateKeys();
    } catch (NoSuchAlgorithmException iae) {
      logger.error(_ERR_NO_SUCH_ALGORITHM, iae);
      throw new EncryptionException(_ERR_NO_SUCH_ALGORITHM, iae);
    } catch (NoSuchPaddingException nspe) {
      logger.error(_ERR_PADDING, nspe);
      throw new EncryptionException(_ERR_PADDING, nspe);
    }
    if (logger.isDebugEnabled()) {
      logger.debug("exiting Constructor");
    }
  }

  /**
   * Encrypts a given plain text String, and returns the encrypted String
   *
   * @param plainText
   * @return
   * @throws EncryptionException
   */
  public String encrypt(String plainText, PublicKey publicKey) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering encrypt");
    }

    String encryptedKey = null;
    try {
      byte[] byteToEncrypt = plainText.getBytes(UTF8);
      cipher.init(Cipher.ENCRYPT_MODE, publicKey);
      byte[] encryptedBytes = cipher.doFinal(byteToEncrypt);
      encryptedKey = DatatypeConverter.printBase64Binary(encryptedBytes);
    } catch (IllegalArgumentException iae) {
      logger.error(_ERR_PASSPHRASE_IS_NULL, iae);
      throw new EncryptionException(_ERR_PASSPHRASE_IS_NULL, iae);
    } catch (InvalidKeyException ike) {
      logger.error(_ERR_INVALIDKEY, ike);
      throw new EncryptionException(_ERR_INVALIDKEY, ike);
    } catch (BadPaddingException bpe) {
      logger.error(_ERR_BAD_PADDING, bpe);
      throw new EncryptionException(_ERR_BAD_PADDING, bpe);
    } catch (IllegalBlockSizeException bpe) {
      logger.error(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
      throw new EncryptionException(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
    } catch (UnsupportedEncodingException uee) {
      logger.error(_ERR_UNSUPPORTED_ENCODING, uee);
      throw new EncryptionException(_ERR_UNSUPPORTED_ENCODING, uee);
    } /*-catch (InvalidAlgorithmParameterException iape) {
      logger.error(_ERR_INVALID_ALGORITHM, iape);
      throw new EncryptionException(_ERR_INVALID_ALGORITHM, iape);
      }*/

    if (logger.isDebugEnabled()) {
      logger.debug("exiting encrypt");
    }

    return encryptedKey;
  }

  /**
   * Decrypts a given encrypted String, and returns the plain text String
   *
   * @param cipherTextStr
   * @return
   * @throws EncryptionException
   */
  public String decrypt(String cipherTextStr, PrivateKey privateKey) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering decrypt");
    }

    String cleartext = null;
    try {
      cipher.init(Cipher.DECRYPT_MODE, privateKey);
      byte[] plainByte = cipher.doFinal(DatatypeConverter.parseBase64Binary(cipherTextStr));
      cleartext = new String(plainByte);
    } /*-catch (InvalidAlgorithmParameterException iape) {
      logger.error(_ERR_INVALID_ALGORITHM, iape);
      throw new EncryptionException(_ERR_INVALID_ALGORITHM, iape);
      } */catch (IllegalArgumentException iae) {
      logger.error(_ERR_PASSPHRASE_IS_NULL, iae);
      throw new EncryptionException(_ERR_PASSPHRASE_IS_NULL, iae);
    } catch (InvalidKeyException ike) {
      logger.error(_ERR_INVALIDKEY, ike);
      throw new EncryptionException(_ERR_INVALIDKEY, ike);
    } catch (BadPaddingException bpe) {
      logger.error(_ERR_BAD_PADDING, bpe);
      throw new EncryptionException(_ERR_BAD_PADDING, bpe);
    } catch (IllegalBlockSizeException bpe) {
      logger.error(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
      throw new EncryptionException(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
    }

    if (logger.isDebugEnabled()) {
      logger.debug("exiting decrypt");
    }

    return cleartext;
  }

  /**
   * Creates the IV using Secure Random Number Generator and an empty 16byte array
   *
   * @return
   */
  private void generateIV() {
    if (logger.isDebugEnabled()) {
      logger.debug("entering generateIV");
    }

    byte[] newSeed = secureRandom.generateSeed(16);
    secureRandom.setSeed(newSeed);
    byte[] byteIV = new byte[16];
    secureRandom.nextBytes(byteIV);
    initVector = new IvParameterSpec(byteIV);

    if (logger.isDebugEnabled()) {
      logger.debug("exiting generateIV");
    }
  }

  /**
   * Generates the Key used for decryption and encryption
   *
   * @throws EncryptionException
   */
  private void generateKeys() throws EncryptionException {

    try {
      String saltStr = "salty";// rbConfig.getString("salt");
      String passPhraseStr = "passy";// rbConfig.getString("passphrase");
      if (StringUtils.isEmpty(saltStr) || StringUtils.isEmpty(passPhraseStr)) {
        throw new EncryptionException(_ERR_PASSPHRASE_IS_NULL);
      }

      KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
      keyGen.initialize(512); // key size specified here.
      KeyPair pair = keyGen.generateKeyPair();
      privateKeyParam = pair.getPrivate();
      publicKeyParam = pair.getPublic();

      /*-byte[] salt = saltStr.getBytes();
      int iterations = 10000;
      int keyLength = 128;

      SecretKeyFactory factory = SecretKeyFactory.getInstance(ALGORITHM);
      SecretKey tmp = factory.generateSecret(new PBEKeySpec(passPhraseStr.toCharArray(), salt, iterations, keyLength));
      secretKey = new SecretKeySpec(tmp.getEncoded(), ALGORITHM_SHORT);*/
    } catch (NoSuchAlgorithmException iae) {
      logger.error(_ERR_NO_SUCH_ALGORITHM, iae);
      throw new EncryptionException(_ERR_NO_SUCH_ALGORITHM, iae);
    } /*-catch (InvalidKeySpecException e) {
      logger.error(_ERR_INVALID_KEY_SPEC, e);
      throw new EncryptionException(_ERR_INVALID_KEY_SPEC, e);
      }*/

  }

  /**
   * Test method
   *
   * @param args
   */
  public static void main(String[] args) {
    String[] message = { "mktest", "9248547896548752345", "okok234234234okok467467",
        "12" };
    String result = null;
    try {
      SecurityTools secTool = new SecurityTools();
      PrivateKey priv = secTool.getPrivateKeyParam();
      PublicKey publ = secTool.getPublicKeyParam();
      String temp = "N5B1zgbvts3Vwrt6qyL/TBzt62HTFz0ISySx5HFu02oVq1YEhFLbrgdCndROX4/5hMpxCHGM8UJBSyZUfjD/DA==";
      // System.out.println("ASYMMETRIC TEST" + secTool.decrypt(temp, priv));

      for (String mess : message) {
        result = secTool.encrypt(mess, publ);
        System.out.println(result);
        result = secTool.decrypt(result, priv);
        System.out.println(result);
      }
    } catch (Exception e) {
      System.out.println(e.getMessage());
      e.printStackTrace();

    }
  }

  /**
   * @return the privateKeyParam
   */
  public PrivateKey getPrivateKeyParam() {
    return privateKeyParam;
  }

  /**
   * @return the publicKeyParam
   */
  public PublicKey getPublicKeyParam() {
    return publicKeyParam;
  }

  class EncryptionException extends Exception {

    private static final long serialVersionUID = 1L;

    public EncryptionException() {}

    public EncryptionException(String message, Throwable cause) {
      super(message, cause);
    }

    public EncryptionException(String message) {
      super(message);
    }

    public EncryptionException(Throwable cause) {
      super(cause);
    }
  }
}

当我按原样运行时，它是可行的，因为主要是一次性进行加密和解密。但是，当我从运行中获取输出，并将其存储在main（）中的临时字符串中，然后取消注释行System.out.println（“ ASYMMETRIC TEST” +时，它会以

失败）

com.ni.apps.cartencryptutil.SecurityTools$EncryptionException: bad padding exception.
    at com.ni.apps.cartencryptutil.SecurityTools.decrypt(SecurityTools.java:154)
    at com.ni.apps.cartencryptutil.SecurityTools.main(SecurityTools.java:239)
Caused by: javax.crypto.BadPaddingException: Decryption error
    at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:380)
    at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:291)
    at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
    at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)
    at javax.crypto.Cipher.doFinal(Cipher.java:2165)
    at com.ni.apps.cartencryptutil.SecurityTools.decrypt(SecurityTools.java:141)
    ... 1 more

我认为我的问题是我每次都重新生成一个新的KeyPair，它只能成对使用一次。因此，一旦我尝试将来自一个KeyPair的PrivateKey与使用完全不同的KeyPair加密的文本进行匹配，它就会失败。但是我还没有找到在那种情况下应该如何实现这一目标的方法。

Answer 1

package com.ni.apps.cartencryptutil;

import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;

import org.apache.commons.lang3.StringUtils;
import org.apache.log4j.Logger;

import com.ni.apps.cartencryptutil.exceptions.EncryptionException;

/**
 * Security class for encrypting and decrypting Strings (that also works in WC ver 7 and above).
 *
 * @author mkohanek
 *
 */
public class SecurityTools {
  private static final Logger logger = Logger.getLogger(SecurityTools.class);

  private Cipher cipher;
  private IvParameterSpec initVector;
  private SecretKey secretKey;
  private transient ResourceBundle rbConfig;

  private static SecureRandom secureRandom = new SecureRandom();
  private static final String AES_ALGORITHM = "AES/CBC/PKCS5Padding";
  private static final String ALGORITHM_SHORT = "AES";
  private static final String PBE_ALGORITHM = "PBEWithMD5AndDES";
  private static final String UTF8 = "UTF-8";
  private static final int ITERATIONS = 10000;
  private static final int KEY_LENGTH = 128;

  // exceptions
  private static final String _ERR_ILLEGAL_BLOCK_SIZE = "illegal block size exception.";
  private static final String _ERR_BAD_PADDING = "bad padding exception.";
  private static final String _ERR_INVALIDKEY = "invalidkey exception.";
  private static final String _ERR_PADDING = "padding exception.";
  private static final String _ERR_NO_SUCH_ALGORITHM = "no such algorithm exception.";
  private static final String _ERR_PASSPHRASE_IS_NULL = "passphrase is null.";
  private static final String _ERR_SALT_IS_NULL = "salt is null.";
  private static final String _ERR_INVALID_ALGORITHM = "invalid algorithm exception.";
  private static final String _ERR_UNSUPPORTED_ENCODING = "encoding not supported.";
  private static final String _ERR_INVALID_KEY_SPEC = "invalid key spec exception.";

  /**
   * Constructor
   *
   * @param salt
   *          - for encryption, obtain salt from generateSalt(). for decryption, you should use the same salt used during encryption
   * @throws EncryptionException
   */
  public SecurityTools(String salt) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering Constructor");
    }
    try {
      loadProperties();
      cipher = Cipher.getInstance(AES_ALGORITHM);
      generateIV(salt);
      generateKey(salt);
    } catch (NoSuchAlgorithmException iae) {
      logger.error(_ERR_NO_SUCH_ALGORITHM, iae);
      throw new EncryptionException(_ERR_NO_SUCH_ALGORITHM, iae);
    } catch (NoSuchPaddingException nspe) {
      logger.error(_ERR_PADDING, nspe);
      throw new EncryptionException(_ERR_PADDING, nspe);
    }
    if (logger.isDebugEnabled()) {
      logger.debug("exiting Constructor");
    }
  }

  /**
   * Constructor
   *
   * @param salt
   *          - for encryption, obtain salt from generateSalt(). for decryption, you should use the same salt used during encryption
   * @param passPhrase
   *          - Allows client to pass in a passphrase it wants to use rather than use the one this library defines. This must also be used when decrypting. The length limit for this key is 16
   *          characters
   * @throws EncryptionException
   */
  public SecurityTools(String salt, String passPhrase) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering Constructor");
    }
    try {
      loadProperties();
      cipher = Cipher.getInstance(AES_ALGORITHM);
      generateIV(salt);
      generateKey(salt, passPhrase);
    } catch (NoSuchAlgorithmException iae) {
      logger.error(_ERR_NO_SUCH_ALGORITHM, iae);
      throw new EncryptionException(_ERR_NO_SUCH_ALGORITHM, iae);
    } catch (NoSuchPaddingException nspe) {
      logger.error(_ERR_PADDING, nspe);
      throw new EncryptionException(_ERR_PADDING, nspe);
    }
    if (logger.isDebugEnabled()) {
      logger.debug("exiting Constructor");
    }
  }

  /**
   * Encrypts a given plain text String, and returns the encrypted String
   *
   * @param plainText
   * @return
   * @throws EncryptionException
   */
  public String encrypt(String plainText) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering encrypt");
    }

    String encryptedKey = null;
    try {
      byte[] byteToEncrypt = plainText.getBytes(UTF8);
      cipher.init(Cipher.ENCRYPT_MODE, secretKey, initVector, new SecureRandom());
      byte[] encryptedBytes = cipher.doFinal(byteToEncrypt);
      encryptedKey = DatatypeConverter.printBase64Binary(encryptedBytes);
    } catch (IllegalArgumentException iae) {
      logger.error(_ERR_PASSPHRASE_IS_NULL, iae);
      throw new EncryptionException(_ERR_PASSPHRASE_IS_NULL, iae);
    } catch (InvalidKeyException ike) {
      logger.error(_ERR_INVALIDKEY, ike);
      throw new EncryptionException(_ERR_INVALIDKEY, ike);
    } catch (BadPaddingException bpe) {
      logger.error(_ERR_BAD_PADDING, bpe);
      throw new EncryptionException(_ERR_BAD_PADDING, bpe);
    } catch (IllegalBlockSizeException bpe) {
      logger.error(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
      throw new EncryptionException(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
    } catch (UnsupportedEncodingException uee) {
      logger.error(_ERR_UNSUPPORTED_ENCODING, uee);
      throw new EncryptionException(_ERR_UNSUPPORTED_ENCODING, uee);
    } catch (InvalidAlgorithmParameterException iape) {
      logger.error(_ERR_INVALID_ALGORITHM, iape);
      throw new EncryptionException(_ERR_INVALID_ALGORITHM, iape);
    }

    if (logger.isDebugEnabled()) {
      logger.debug("exiting encrypt");
    }

    return encryptedKey;
  }

  /**
   * Decrypts a given encrypted String, and returns the plain text String
   *
   * @param cipherTextStr
   * @return
   * @throws EncryptionException
   */
  public String decrypt(String cipherTextStr) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering decrypt");
    }

    String cleartext = null;
    try {
      cipher.init(Cipher.DECRYPT_MODE, secretKey, initVector);
      byte[] plainByte = cipher.doFinal(DatatypeConverter.parseBase64Binary(cipherTextStr));
      cleartext = new String(plainByte);
    } catch (InvalidAlgorithmParameterException iape) {
      logger.error(_ERR_INVALID_ALGORITHM, iape);
      throw new EncryptionException(_ERR_INVALID_ALGORITHM, iape);
    } catch (IllegalArgumentException iae) {
      logger.error(_ERR_PASSPHRASE_IS_NULL, iae);
      throw new EncryptionException(_ERR_PASSPHRASE_IS_NULL, iae);
    } catch (InvalidKeyException ike) {
      logger.error(_ERR_INVALIDKEY, ike);
      throw new EncryptionException(_ERR_INVALIDKEY, ike);
    } catch (BadPaddingException bpe) {
      logger.error(_ERR_BAD_PADDING, bpe);
      throw new EncryptionException(_ERR_BAD_PADDING, bpe);
    } catch (IllegalBlockSizeException bpe) {
      logger.error(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
      throw new EncryptionException(_ERR_ILLEGAL_BLOCK_SIZE, bpe);
    }

    if (logger.isDebugEnabled()) {
      logger.debug("exiting decrypt");
    }

    return cleartext;
  }

  /**
   * Creates the IV using Secure Random Number Generator and an empty 16byte array
   *
   * @return
   */
  private void generateIV(String salt) {
    if (logger.isDebugEnabled()) {
      logger.debug("entering generateIV");
    }

    byte[] newSeed = DatatypeConverter.parseBase64Binary(salt);
    initVector = new IvParameterSpec(newSeed);

    if (logger.isDebugEnabled()) {
      logger.debug("exiting generateIV");
    }
  }

  /**
   * Generates the Key used for decryption and encryption using passphrase from properties file on library
   *
   ** @param saltStr
   * @return
   * @throws EncryptionException
   */
  private void generateKey(String saltStr) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering generateKey");
    }

    try {
      String passPhraseStr = rbConfig.getString("passphrase");
      if (StringUtils.isEmpty(passPhraseStr)) {
        throw new EncryptionException(_ERR_PASSPHRASE_IS_NULL);
      }
      if (StringUtils.isEmpty(saltStr)) {
        throw new EncryptionException(_ERR_SALT_IS_NULL);
      }

      byte[] salt = DatatypeConverter.parseBase64Binary(saltStr);

      SecretKeyFactory factory = SecretKeyFactory.getInstance(PBE_ALGORITHM);
      SecretKey tmp = factory.generateSecret(new PBEKeySpec(passPhraseStr.toCharArray(), salt, ITERATIONS, KEY_LENGTH));
      secretKey = new SecretKeySpec(tmp.getEncoded(), ALGORITHM_SHORT);
    } catch (NoSuchAlgorithmException iae) {
      logger.error(_ERR_NO_SUCH_ALGORITHM, iae);
      throw new EncryptionException(_ERR_NO_SUCH_ALGORITHM, iae);
    } catch (InvalidKeySpecException e) {
      logger.error(_ERR_INVALID_KEY_SPEC, e);
      throw new EncryptionException(_ERR_INVALID_KEY_SPEC, e);
    }

    if (logger.isDebugEnabled()) {
      logger.debug("exiting generateKey");
    }
  }

  /**
   * Generates the Key used for decryption and encryption using passphrase passed in
   *
   * @param saltStr
   * @param passPhrase
   * @throws EncryptionException
   */
  private void generateKey(String saltStr, String passPhrase) throws EncryptionException {
    if (logger.isDebugEnabled()) {
      logger.debug("entering generateKey");
    }

    try {
      if (StringUtils.isEmpty(passPhrase)) {
        throw new EncryptionException(_ERR_PASSPHRASE_IS_NULL);
      }
      if (StringUtils.isEmpty(saltStr)) {
        throw new EncryptionException(_ERR_SALT_IS_NULL);
      }

      byte[] salt = DatatypeConverter.parseBase64Binary(saltStr);

      SecretKeyFactory factory = SecretKeyFactory.getInstance(PBE_ALGORITHM);
      SecretKey tmp = factory.generateSecret(new PBEKeySpec(passPhrase.toCharArray(), salt, ITERATIONS, KEY_LENGTH));
      secretKey = new SecretKeySpec(tmp.getEncoded(), ALGORITHM_SHORT);
    } catch (NoSuchAlgorithmException iae) {
      logger.error(_ERR_NO_SUCH_ALGORITHM, iae);
      throw new EncryptionException(_ERR_NO_SUCH_ALGORITHM, iae);
    } catch (InvalidKeySpecException e) {
      logger.error(_ERR_INVALID_KEY_SPEC, e);
      throw new EncryptionException(_ERR_INVALID_KEY_SPEC, e);
    }

    if (logger.isDebugEnabled()) {
      logger.debug("exiting generateKey");
    }
  }

  /**
   * This generates a random value of user defined size that can be used to encrypt data. The decrypting client will then need to access this value to be able to decrypt
   *
   * @return
   */
  public static String generateSaltStr(int size) {
    String salt = null;
    byte[] newSeed = secureRandom.generateSeed(size);
    salt = DatatypeConverter.printBase64Binary(newSeed);

    return salt;
  }

  /**
   * This generates a random 16 bit value that can be used to encrypt data. The decrypting client will then need to access this value to be able to decrypt
   *
   * @return
   */
  public static String generateSaltStr() {
    String salt = null;
    byte[] newSeed = secureRandom.generateSeed(16);
    salt = DatatypeConverter.printBase64Binary(newSeed);

    return salt;
  }

  /**
   * Loads properties files (call before attempting to read any properties files)
   */
  private void loadProperties() {
    try {
      rbConfig = ResourceBundle.getBundle("application", Locale.US);
    } catch (MissingResourceException ie) {
      logger.fatal(
          "FATAL: SecurityTools.loadProperties Cannot read the properties file.  Please ensure the file is on the classpath.");
    } catch (Exception e) {
      logger.fatal(
          "FATAL: SecurityTools.loadProperties Cannot read the properties file.  Please ensure the file is on the classpath.");
    }
  }

  /**
   * Test method
   *
   * @param args
   */
  public static void main(String[] args) {
    String[] message = { "mkohanek", "9248547896548752345", "okok234234234okok467467",
        "12" };
    String result = null;
    try {
      // ASYMMETRIC TEST - use this block to test values are usable over separate sessions by taking output from loop below and using it here for subsequent calls
      // String previousSalt = "jriUh+01HlHw4g3mO9PLcw==";
      // SecurityTools asSecTool = new SecurityTools(previousSalt);
      // String previousEncryptedValue = "nFVxkzdx+psiUVkCW5NztQ==";
      // System.out.println("should decrypt to an expected value - " + asSecTool.decrypt(previousEncryptedValue));
      // END ASYMMETRIC TEST

      // SYMMETRIC TEST - tests that single requests will encrypt and decrypt successfully
      String salt = generateSaltStr(16);
      System.out.println("salt - " + salt);
      SecurityTools secTool = new SecurityTools(salt);
      for (String mess : message) {
        result = secTool.encrypt(mess);
        System.out.println(result);
        result = secTool.decrypt(result);
        System.out.println(result);
      }
      // END SYMMETRIC TEST
    } catch (Exception e) {
      System.out.println(e.getMessage());
      e.printStackTrace();

    }
  }

}