通用加密技术学习笔记

import java.security.MessageDigest;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class EncryptManager
{

    public static byte[] TripleDES_CBC_Encrypt(byte[] sourceBuf, SecretKeySpec deskey, IvParameterSpec ivParam)
            throws Exception
    {
        byte[] cipherByte;
        Cipher encrypt = Cipher.getInstance("TripleDES/CBC/PKCS5Padding");

        encrypt.init(Cipher.ENCRYPT_MODE, deskey, ivParam);

        cipherByte = encrypt.doFinal(sourceBuf, 0, sourceBuf.length);
        return cipherByte;
    }

    public static byte[] TripleDES_CBC_Decrypt(byte[] sourceBuf, SecretKeySpec deskey, IvParameterSpec ivParam)
            throws Exception
    {

        byte[] cipherByte;
        Cipher decrypt = Cipher.getInstance("TripleDES/CBC/PKCS5Padding");
        decrypt.init(Cipher.DECRYPT_MODE, deskey, ivParam);

        cipherByte = decrypt.doFinal(sourceBuf, 0, sourceBuf.length);
        return cipherByte;
    }

    public static byte[] DES_CBC_Encrypt(byte[] sourceBuf, SecretKeySpec deskey, IvParameterSpec ivParam)
            throws Exception
    {
        byte[] cipherByte;
        Cipher encrypt = Cipher.getInstance("DES/CBC/PKCS5Padding");

        encrypt.init(Cipher.ENCRYPT_MODE, deskey, ivParam);

        cipherByte = encrypt.doFinal(sourceBuf, 0, sourceBuf.length);
        return cipherByte;
    }

    public static byte[] DES_CBC_Decrypt(byte[] sourceBuf, SecretKeySpec deskey, IvParameterSpec ivParam)
            throws Exception
    {

        byte[] cipherByte;
        Cipher decrypt = Cipher.getInstance("DES/CBC/PKCS5Padding");
        decrypt.init(Cipher.DECRYPT_MODE, deskey, ivParam);

        cipherByte = decrypt.doFinal(sourceBuf, 0, sourceBuf.length);
        return cipherByte;
    }

    public static byte[] DES_ECB_Encrypt(byte[] sourceBuf, SecretKeySpec deskey) throws Exception
    {

        byte[] cipherByte;
        Cipher encrypt = Cipher.getInstance("DES");

        encrypt.init(Cipher.ENCRYPT_MODE, deskey);

        cipherByte = encrypt.doFinal(sourceBuf, 0, sourceBuf.length);

        return cipherByte;
    }

    public static byte[] DES_ECB_Decrypt(byte[] sourceBuf, SecretKeySpec deskey) throws Exception
    {

        byte[] cipherByte;
        Cipher decrypt = Cipher.getInstance("DES");

        decrypt.init(Cipher.DECRYPT_MODE, deskey);

        cipherByte = decrypt.doFinal(sourceBuf, 0, sourceBuf.length);

        return cipherByte;
    }

    public static byte[] MD5Hash(byte[] buf, int offset, int length) throws Exception
    {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(buf, offset, length);
        return md.digest();
    }

    public static String byte2hex(byte[] inStr)
    {
        String stmp;
        StringBuffer out = new StringBuffer(inStr.length * 2);

        for (int n = 0; n < inStr.length; n++)
        {
            stmp = Integer.toHexString(inStr[n] & 0xFF);
            if (stmp.length() == 1)
            {
                out.append("0" + stmp);
            }
            else
            {
                out.append(stmp);
            }
        }
        return out.toString();
    }

    public static byte[] addMD5(byte[] md5Byte, byte[] bodyByte)
    {
        int length = bodyByte.length + md5Byte.length;
        byte[] resutlByte = new byte[length];

        for (int i = 0; i < length; i++)
        {
            if (i < md5Byte.length)
            {
                resutlByte[i] = md5Byte[i];
            }
            else
            {
                resutlByte[i] = bodyByte[i - md5Byte.length];
            }
        }

        return resutlByte;
    }

}