小编use*_*937的帖子

我是密码学的新手，所以我有一个问题：

我如何创建自己的密钥（比如字符串“1234”）。因为我需要用密钥（由我定义）加密一个字符串，将加密的字符串保存在数据库中，当我想使用它时，从数据库中取出它并用我知道的密钥解密。

我有这个代码：

   import java.security.InvalidKeyException;
   import java.security.*;
   import javax.crypto.BadPaddingException;
   import javax.crypto.Cipher;
   import javax.crypto.IllegalBlockSizeException;
   import javax.crypto.SecretKey;
   import javax.crypto.SecretKeyFactory;
   import javax.crypto.spec.DESedeKeySpec;

      public class LocalEncrypter {

    private static String algorithm = "PBEWithMD5AndDES";
   //private static Key key = null;
    private static Cipher cipher = null;
    private static SecretKey key;

    private static void setUp() throws Exception {
        ///key = KeyGenerator.getInstance(algorithm).generateKey();
        SecretKeyFactory factory = SecretKeyFactory.getInstance(algorithm);
        String pass1 = "thisIsTheSecretKeyProvidedByMe";
        byte[] pass = pass1.getBytes(); 
        SecretKey key = factory.generateSecret(new DESedeKeySpec(pass));
        cipher = Cipher.getInstance(algorithm);
    }

    public static void main(String[] …