資格認(rèn)證:Java中3DES加密解密調(diào)用示例

在java中調(diào)用sun公司提供的3DES加密解密算法時(shí)，需要使用到$JAVA_HOME/jre/lib/目錄下如下的4個(gè)jar包：
    jce.jar
    security/US_export_policy.jar
    security/local_policy.jar
    ext/sunjce_provider.jar
    Java運(yùn)行時(shí)會(huì)自動(dòng)加載這些包，因此對于帶main函數(shù)的應(yīng)用程序不需要設(shè)置到CLASSPATH環(huán)境變量中。對于WEB應(yīng)用，不需要把這些包加到WEB-INF/lib目錄下。
    以下是java中調(diào)用sun公司提供的3DES加密解密算法的樣本代碼：
    /*字符串 DESede(3DES) 加密*/
    import java.security.*;
    import javax.crypto.*;
    import javax.crypto.spec.SecretKeySpec;
    public class ThreeDes {
    private static final String Algorithm = "DESede"; //定義 加密算法,可用 DES,DESede,Blowfish
    //keybyte為加密密鑰，長度為24字節(jié)
    //src為被加密的數(shù)據(jù)緩沖區(qū)（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);
    }
    catch (java.security.NoSuchAlgorithmException e1) {
    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字節(jié)
    //src為加密后的緩沖區(qū)
    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) {
    e1.printStackTrace();
    }
    catch (javax.crypto.NoSuchPaddingException e2) {
    e2.printStackTrace();
    }
    catch (java.lang.Exception e3) {
    e3.printStackTrace();
    }
    return null;
    }
    //轉(zhuǎn)換成十六進(jìn)制字符串
    public static String byte2hex(byte[] b) {
    String hs="";
    String stmp="";
    for (int n=0;n    stmp=(java.lang.Integer.toHexString(b[n] & 0XFF));
    if (stmp.length()==1) hs=hs+"0"+stmp;
    else hs=hs+stmp;
    if (n    }
    return hs.toUpperCase();
    }
    public static void main(String[] args){
    //添加新安全算法,如果用JCE就要把它添加進(jìn)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字節(jié)的密鑰
    String szSrc = "This is a 3DES test. 測試";
    System.out.println("加密前的字符串:" + szSrc);
    byte[] encoded = encryptMode(keyBytes, szSrc.getBytes());
    System.out.println("加密后的字符串:" + new String(encoded));
    byte[] srcBytes = decryptMode(keyBytes, encoded);
    System.out.println("解密后的字符串:" + (new String(srcBytes)));
    }
    }