JAVA implements DES encryption and decryption __java

Des.java

Import java.security.*;

Import javax.crypto.*;
	/** * des plus decryption algorithm * * public class DES {private static String Strdefaultkey = "abcDEF123";
	Private Cipher encryptcipher = null;


	Private Cipher decryptcipher = null;
	/** * Default construction method, using the default key * @throws Exception/Public DES () throws Exception {this (Strdefaultkey); /** * Specifies the key construction method * @param strkey specified key * @throws Exception/Public DES (String strkey) throws Exception {S
		Ecurity.addprovider (New Com.sun.crypto.provider.SunJCE ());
		Key key = Getkey (Strkey.getbytes ());
		Encryptcipher = Cipher.getinstance ("DES");
		Encryptcipher.init (Cipher.encrypt_mode, key);
		Decryptcipher = Cipher.getinstance ("DES");
	Decryptcipher.init (Cipher.decrypt_mode, key); /** * Encrypt String * @param strin strings to be encrypted * @return Encrypted String * @throws Exception/public string encrypt (string s
	Trin) throws Exception {return bytearr2hexstr Encrypt (Strin.getbytes ()));
/** * Encrypted byte array * @param ARRB byte array to encrypt * @return encrypted byte array	 * @throws Exception/public byte[] Encrypt (byte[] arrb) throws Exception {return encryptcipher.dofinal (ARRB); /** * Decryption String * @param strin string to Decrypt * @return decrypted String * @throws Exception/public string decrypt (Strin
	G Strin) throws Exception {return new String (Decrypt (Hexstr2bytearr (Strin))); /** * Decrypt byte array * @param ARRB byte array to decrypt * @return decrypted byte array * @throws Exception/public byte[] Decrypt (byte
	[] Arrb throws Exception {return decryptcipher.dofinal (ARRB); /** * Generates the key from the specified string, the key requires a byte array length of 8 bits * less than 8 bits after 0, more than 8 bit only the first 8 bits * @param arrbtmp the byte array that makes up the string * @return the generated key * @thr
		OWS java.lang.Exception * * Private Key Getkey (byte[] arrbtmp) throws Exception {byte[] arrb = new Byte[8];
		for (int i = 0; i < arrbtmp.length && i < arrb.length; i++) {arrb[i] = Arrbtmp[i];
		Key key = new Javax.crypto.spec.SecretKeySpec (ARRB, "DES");
	Return key;
/** * Converts a byte array to a string representing a 16-valued value, * such as: byte[]{8,18} converted to: 0813,	 * and public static byte[] Hexstr2bytearr (string strin) * Mutually reversible conversion process * @param ARRB byte array to convert * @return converted String * @ Throws Exception This method does not handle any exceptions, all exceptions are thrown */public static String Bytearr2hexstr (byte[] arrb) throws Exception {int Ilen
		= Arrb.length;
		StringBuffer sb = new StringBuffer (Ilen * 2);
			for (int i = 0; i < Ilen i++) {int inttmp = arrb[i];
			while (Inttmp < 0) {inttmp = inttmp + 256;
			} if (Inttmp <) {Sb.append ("0");
		} sb.append (Integer.tostring (inttmp, 16));
	return sb.tostring ();  /** * Converts a string representing a value of 16 into a byte array, * and public static string Bytearr2hexstr (byte[] arrb) * Mutually reversible conversion process * @param strin The string that needs to be converted * @return the converted byte array * @throws Exception This method does not handle any exceptions, all exceptions throw the/public static byte[] Hexstr2bytearr (strin
		G Strin) throws Exception {byte[] arrb = Strin.getbytes ();
		int ilen = Arrb.length;
		byte[] Arrout = new BYTE[ILEN/2]; for (int i = 0; i < ilen i = i + 2) {String strtmp = new String (ARRB, I, 2);
		ARROUT[I/2] = (byte) integer.parseint (strtmp, 16);
	return arrout;
 }


}

Encryutil.java

/**
 * Cryptographic decryption Tool class/public
class Encryutil {
	
	/**
	 * Using the default key for DES encryption/public
	static String Encrypt (String plaintext) {
		try {return
			new DES (). Encrypt (plaintext);
		\ catch (Exception e) {
			return null;
		}

	
	/**
	 * Using the specified key for des decryption
	/public static string encrypt (string plaintext, string key) {
		try {
			return new DES (key). Encrypt (plaintext);
		catch (Exception e) {return
			null;
		}
	}
	

	/**
	 * Use default key for DES decryption
	 /public
	static string decrypt (string plaintext) {
		try {return
			new DES () . Decrypt (plaintext);
		catch (Exception e) {return
			null;
		}
	}

	
	/**
	 * Using the specified key for des decryption
	/public static string decrypt (string plaintext, string key) {
		try {
			return new DES (key). Decrypt (plaintext);
		catch (Exception e) {return
			null;
		}
	}

}

Testdes.java

public class Testdes {public
	
	static void Main (string[] args) throws Exception {
		String str = "01234abcdabcd!@#$";
		String t = "";
		SYSTEM.OUT.PRINTLN ("Encrypted:" + (t = encryutil.encrypt (str));
		System.out.println ("After decryption:" + encryutil.decrypt (t));
	}