DES.java
import java.security.*;
import javax.crypto.*;
/**
* DES加解密算法
*/
public class DES {
private static String strDefaultKey = "abcDEF123";
private Cipher encryptCipher = null;
private Cipher decryptCipher = null;
/**
* 默認構造方法,使用默認密鑰
* @throws Exception
*/
public DES() throws Exception {
this(strDefaultKey);
}
/**
* 指定密鑰構造方法
* @param strKey 指定的密鑰
* @throws Exception
*/
public DES(String strKey) throws Exception {
Security.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);
}
/**
* 加密字符串
* @param strIn 需加密的字符串
* @return 加密後的字符串
* @throws Exception
*/
public String encrypt(String strIn) throws Exception {
return byteArr2HexStr(encrypt(strIn.getBytes()));
}
/**
* 加密字節數組
* @param arrB 需加密的字節數組
* @return 加密後的字節數組
* @throws Exception
*/
public byte[] encrypt(byte[] arrB) throws Exception {
return encryptCipher.doFinal(arrB);
}
/**
* 解密字符串
* @param strIn 需解密的字符串
* @return 解密後的字符串
* @throws Exception
*/
public String decrypt(String strIn) throws Exception {
return new String(decrypt(hexStr2ByteArr(strIn)));
}
/**
* 解密字節數組
* @param arrB 需解密的字節數組
* @return 解密後的字節數組
* @throws Exception
*/
public byte[] decrypt(byte[] arrB) throws Exception {
return decryptCipher.doFinal(arrB);
}
/**
* 從指定字符串生成密鑰,密鑰所需的字節數組長度爲8位
* 不足8位時後面補0,超出8位只取前8位
* @param arrBTmp 構成該字符串的字節數組
* @return 生成的密鑰
* @throws 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;
}
/**
* 將byte數組轉換爲表示16進制值的字符串,
* 如:byte[]{8,18}轉換爲:0813,
* 和public static byte[] hexStr2ByteArr(String strIn)
* 互爲可逆的轉換過程
* @param arrB 需要轉換的byte數組
* @return 轉換後的字符串
* @throws Exception 本方法不處理任何異常,所有異常全部拋出
*/
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 < 16) {
sb.append("0");
}
sb.append(Integer.toString(intTmp, 16));
}
return sb.toString();
}
/**
* 將表示16進制值的字符串轉換爲byte數組,
* 和public static String byteArr2HexStr(byte[] arrB)
* 互爲可逆的轉換過程
* @param strIn 需要轉換的字符串
* @return 轉換後的byte數組
* @throws Exception 本方法不處理任何異常,所有異常全部拋出
*/
public static byte[] hexStr2ByteArr(String 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
/**
* 加密解密工具類
*/
public class EncryUtil {
/**
* 使用默認密鑰進行DES加密
*/
public static String encrypt(String plainText) {
try {
return new DES().encrypt(plainText);
} catch (Exception e) {
return null;
}
}
/**
* 使用指定密鑰進行DES解密
*/
public static String encrypt(String plainText, String key) {
try {
return new DES(key).encrypt(plainText);
} catch (Exception e) {
return null;
}
}
/**
* 使用默認密鑰進行DES解密
*/
public static String decrypt(String plainText) {
try {
return new DES().decrypt(plainText);
} catch (Exception e) {
return null;
}
}
/**
* 使用指定密鑰進行DES解密
*/
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("加密後:" + (t = EncryUtil.encrypt(str)));
System.out.println("解密後:" + EncryUtil.decrypt(t));
}
}