des解密java

『壹』 java中DES、MD5加密演算法在哪個包中如何分別調用這兩個方法實現對輸入數據的加密、解密

java.security.MessageDigest

/*
*MD5演算法
*/
publicclassMD5{

//全局數組
privatefinalstaticString[]strDigits={"0","1","2","3","4","5",
"6","7","8","9","a","b","c","d","e","f"};

publicMD5(){
}

//返回形式為數字跟字元串
(bytebByte){
intiRet=bByte;
//System.out.println("iRet="+iRet);
if(iRet<0){
iRet+=256;
}
intiD1=iRet/16;
intiD2=iRet%16;
returnstrDigits[iD1]+strDigits[iD2];
}

//返回形式只為數字
privatestaticStringbyteToNum(bytebByte){
intiRet=bByte;
System.out.println("iRet1="+iRet);
if(iRet<0){
iRet+=256;
}
returnString.valueOf(iRet);
}

//轉換位元組數組為16進制字串
(byte[]bByte){
StringBuffersBuffer=newStringBuffer();
for(inti=0;i<bByte.length;i++){
sBuffer.append(byteToArrayString(bByte[i]));
}
returnsBuffer.toString();
}

publicstaticStringGetMD5Code(StringstrObj){
StringresultString=null;
try{
resultString=newString(strObj);
MessageDigestmd=MessageDigest.getInstance("MD5");
//md.digest()該函數返回值為存放哈希值結果的byte數組
resultString=byteToString(md.digest(strObj.getBytes()));
}catch(NoSuchAlgorithmExceptionex){
ex.printStackTrace();
}
returnresultString;
}

publicstaticvoidmain(String[]args){
MD5getMD5=newMD5();
System.out.println(getMD5.GetMD5Code("000000"));
}
}

『貳』 DES加密演算法 java實現

c語言的源代碼，供參考：

http://hi..com/gaojinshan/blog/item/8b2710c4ece4b3ce39db49e9.html

『叄』 如何用Java進行3DES加密解密

這里是例子，直接拿來用就可以了。
package com.nnff.des;

import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/*字元串 DESede(3DES) 加密
* ECB模式/使用PKCS7方式填充不足位,目前給的密鑰是192位
* 3DES（即Triple DES）是DES向AES過渡的加密演算法（1999年，NIST將3-DES指定為過渡的
* 加密標准），是DES的一個更安全的變形。它以DES為基本模塊，通過組合分組方法設計出分組加
* 密演算法，其具體實現如下：設Ek()和Dk()代表DES演算法的加密和解密過程，K代表DES演算法使用的
* 密鑰，P代表明文，C代表密表，這樣，
* 3DES加密過程為：C=Ek3(Dk2(Ek1(P)))
* 3DES解密過程為：P=Dk1((EK2(Dk3(C)))
* */
public class ThreeDes {

/**
* @param args在java中調用sun公司提供的3DES加密解密演算法時，需要使
* 用到$JAVA_HOME/jre/lib/目錄下如下的4個jar包：
*jce.jar
*security/US_export_policy.jar
*security/local_policy.jar
*ext/sunjce_provider.jar
*/

private static final String Algorithm = "DESede"; //定義加密演算法,可用 DES,DESede,Blowfish
//keybyte為加密密鑰，長度為24位元組
//src為被加密的數據緩沖區（源）
public static byte[] encryptMode(byte[] keybyte,byte[] src){
try {
//生成密鑰
SecretKey deskey = new SecretKeySpec(keybyte, Algorithm);
//加密
Cipher c1 = Cipher.getInstance(Algorithm);
c1.init(Cipher.ENCRYPT_MODE, deskey);
return c1.doFinal(src);//在單一方面的加密或解密
} catch (java.security.NoSuchAlgorithmException e1) {
// TODO: handle exception
e1.printStackTrace();
}catch(javax.crypto.NoSuchPaddingException e2){
e2.printStackTrace();
}catch(java.lang.Exception e3){
e3.printStackTrace();
}
return null;
}

//keybyte為加密密鑰，長度為24位元組
//src為加密後的緩沖區
public static byte[] decryptMode(byte[] keybyte,byte[] src){
try {
//生成密鑰
SecretKey deskey = new SecretKeySpec(keybyte, Algorithm);
//解密
Cipher c1 = Cipher.getInstance(Algorithm);
c1.init(Cipher.DECRYPT_MODE, deskey);
return c1.doFinal(src);
} catch (java.security.NoSuchAlgorithmException e1) {
// TODO: handle exception
e1.printStackTrace();
}catch(javax.crypto.NoSuchPaddingException e2){
e2.printStackTrace();
}catch(java.lang.Exception e3){
e3.printStackTrace();
}
return null;
}

//轉換成十六進制字元串
public static String byte2Hex(byte[] b){
String hs="";
String stmp="";
for(int n=0; n<b.length; n++){
stmp = (java.lang.Integer.toHexString(b[n]& 0XFF));
if(stmp.length()==1){
hs = hs + "0" + stmp;
}else{
hs = hs + stmp;
}
if(n<b.length-1)hs=hs+":";
}
return hs.toUpperCase();
}
public static void main(String[] args) {
// TODO Auto-generated method stub
//添加新安全演算法,如果用JCE就要把它添加進去
Security.addProvider(new com.sun.crypto.provider.SunJCE());
final byte[] keyBytes = {0x11, 0x22, 0x4F, 0x58,
(byte)0x88, 0x10, 0x40, 0x38, 0x28, 0x25, 0x79, 0x51,
(byte)0xCB,
(byte)0xDD, 0x55, 0x66, 0x77, 0x29, 0x74,
(byte)0x98, 0x30, 0x40, 0x36,
(byte)0xE2
}; //24位元組的密鑰
String szSrc = "This is a 3DES test. 測試";
System.out.println("加密前的字元串:" + szSrc);
byte[] encoded = encryptMode(keyBytes,szSrc.getBytes());
System.out.println("加密後的字元串:" + new String(encoded));

byte[] srcBytes = decryptMode(keyBytes,encoded);
System.out.println("解密後的字元串:" + (new String(srcBytes)));
}
}

『肆』 des解密演算法，利用C語言解密JAVA語言加密的密碼。。密鑰為12345678，加密後的密文為：26d086be3a3a62fc

// C 語言 DES用的是 ECB模式， 沒有填充
// 因此Java端要對應， 你的明文是 liubiao
嗎？
// 另外 DES已經不安全了， 如果可以改為 3DES或者 AES吧。
public class LearnDes {

public static void main(String[] args) {
try {
System.out.println(encrypt("liubiao", "12345678"));

System.out.println(decrypt("26d086be3a3a62fc", "12345678"));
} catch (Exception e) {
e.printStackTrace();
}
}
public static String encrypt(String message, String key) throws Exception {
//Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
Cipher cipher = Cipher.getInstance("DES/ECB/NOPADDING");

DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));

SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));
//cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);
cipher.init(Cipher.ENCRYPT_MODE, secretKey );

return toHexString(cipher.doFinal(message.getBytes("UTF-8")));
}

public static String decrypt(String message, String key) throws Exception {

byte[] bytesrc = convertHexString(message);

//Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
Cipher cipher = Cipher.getInstance("DES/ECB/NOPADDING");
DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));

//cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);
cipher.init(Cipher.DECRYPT_MODE, secretKey );

byte[] retByte = cipher.doFinal(bytesrc);
return new String(retByte);
}

public static byte[] convertHexString(String ss) {
byte digest[] = new byte[ss.length() / 2];
for (int i = 0; i < digest.length; i++) {
String byteString = ss.substring(2 * i, 2 * i + 2);
int byteValue = Integer.parseInt(byteString, 16);
digest[i] = (byte) byteValue;
}

return digest;
}
public static String toHexString(byte b[]) {
StringBuffer hexString = new StringBuffer();
for (int i = 0; i < b.length; i++) {
String plainText = Integer.toHexString(0xff & b[i]);
if (plainText.length() < 2)
plainText = "0" + plainText;
hexString.append(plainText);
}

return hexString.toString();
}
}

『伍』 如何使用JAVA實現對字元串的DES加密和解密

/**
*ECB模式的des加密，以base64的編碼輸出
*@parammessage
*@paramkey
*@return
*@throwsException
*/
publicstaticStringdesEncrypt(Stringmessage,Stringkey)throwsException{
//DES/ECBCBCCFBOFB/PKCS5PaddingNoPadding加密/模式/填充
Ciphercipher=Cipher.getInstance("DES");//默認就是DES/ECB/PKCS5Padding
DESKeySpecdesKeySpec=newDESKeySpec(key.getBytes());
SecretKeyFactorykeyFactory=SecretKeyFactory.getInstance("DES");
SecretKeysecretKey=keyFactory.generateSecret(desKeySpec);
cipher.init(1,secretKey);
returnnewBASE64Encoder().encode(cipher.doFinal(message.getBytes("UTF-8")));
}
/**
*ECB模式的des解密
*@parammessage
*@paramkey
*@return
*@throwsException
*/
publicstaticStringdesDecrypt(Stringmessage,Stringkey)throwsException{
Ciphercipher=Cipher.getInstance("DES");
DESKeySpecdesKeySpec=newDESKeySpec(key.getBytes());
SecretKeyFactorykeyFactory=SecretKeyFactory.getInstance("DES");
SecretKeysecretKey=keyFactory.generateSecret(desKeySpec);
cipher.init(2,secretKey);
returnnewString(cipher.doFinal(Base64.decode(message)),"UTF-8");
}

你自己寫main方法測試一下，應該是沒問題的

『陸』 使用C# DES解密java DES加密的字元串

Cipher.getInstance("DES/CBC/PKCS5Padding");
裡面的值要設置為同樣的，這樣才能通過密鑰解密。