Java最简单的DES加密算法实现案例

Java最简单的DES加密算法实现案例

Base64.java

package com.mstf.des;

import java.io.UnsupportedEncodingException;

/**

* base64编码/解码

* @author ceet

*

*/

public class Base64 {

public static String encode(String data) {

return new String(encode(data.getBytes()));

}

public static String decode(String data) {

try {

return new String(decode(data.toCharArray()),"utf-8");

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

return null;

}

}

private static char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="

.toCharArray();

private static byte[] codes = new byte[256];

static {

for (int i = 0; i < 256; i++) {

codes[i] = -1;

}

for (int i = 'A'; i <= 'Z'; i++) {

codes[i] = (byte) (i - 'A');

}

for (int i = 'a'; i <= 'z'; i++) {

codes[i] = (byte) (26 + i - 'a');

}

for (int i = '0'; i <= '9'; i++) {

codes[i] = (byte) (52 + i - '0');

}

codes['+'] = 62;

codes['/'] = 63;

}

public static char[] encode(byte[] data) {

char[] out = new char[((data.length + 2) / 3) * 4];

for (int i = 0, index = 0; i < data.length; i += 3, index += 4) {

boolean quad = false;

boolean trip = false;

int val = (0xFF & (int) data[i]);

val <<= 8;

if ((i + 1) < data.lenghttp://th) {

val |= (0xFF & (int) data[i + 1]);

trip = true;

}

val <<= 8;

if ((i + 2) < data.length) {

val |= (0xFF & (int) data[i + 2]KlEcddabl);

quad = true;

}

out[index + 3] = alphabet[(quad ? (val & 0x3F) : 64)];

val >>= 6;

out[index + 2] = alphabet[(trip ? (val & 0x3F) : 64)];

val >>= 6;

out[index + 1] = alphabet[val & 0x3F];

val >>= 6;

out[index + 0] = alphabet[val & 0x3F];

}

return out;

}

public static byte[] decode(char[] data) {

int tempLen = data.length;

for (int ix = 0; ix < data.length; ix++) {

if ((data[ix] > 255) || codes[data[ix]] < 0) {

--tempLen;

}

}

int len = (tempLen / 4) * 3;

if ((tempLen % 4) == 3) {

len += 2;

}

if ((tempLen % 4) == 2) {

len += 1;

}

byte[] out = new byte[len];

int shift = 0;

int accum = 0;

int index = 0;

for (int ix = 0; ix < data.length; ix++) {

int value = (data[ix] > 255) ? -1 : codes[data[ix]];

if (value >= 0) {

accum <<= 6;

shift += 6;

accum |= value;

if (shift >= 8) {

shift -= 8;

out[index++] = (byte) ((accum >> shift) & 0xff);

}

}

}

if (index != out.length) {

throw new Error("Miscalculated data length (wrote " + index

+ " instead of " + out.length + ")");

}

return out;

}

}

DESUtil.java

package com.mstf.des;

import java.security.Key;

import java.security.SecureRandom;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

/**

* DES对称算法(加密/解密)

*

* @author ceet

*

*/

public class DESUtil {

private Key key;

public DESUtil(String strKey) {

setKey(strKey);

}

public void setKey(String strKey) {

try {

KeyGenerator generator = KeyGenerator.getInstance("DES");

generator.init(new SecureRandom(strKey.getBytes())); // 根据参数生成key

this.key = generator.generateKey();

} catch (Exception e) {

e.printStackTrace();

}

}

public String encrypt(String source) {

return encrypt(source, "utf-8");

}

public String decrypt(String encryptedData) {

return decrypt(encryptedData, "utf-8");

}

public String encrypt(String source, String charSet) {

String encrypt = null;

try {

byte[] ret = encrypt(source.getBytes(charSet));

encrypt = new String(Base64.encode(ret));

} catch (Exception e) {

e.printStackTrace();

encrypt = null;

}

return encrypt;

}

public String decrypt(String encryptedData, String charSet) {

String descryptedData = null;

try {

byte[] ret = descrypt(Base64.decode(encryptedData.toCharArray()));

descryptedData = new String(ret, charSet);

} catch (Exception e) {

e.printStackTrace();

descryptedData = null;

}

return descryptedData;

}

private byte[] encrypt(byte[] primaryData) {

try {

Cipher cipher = Cipher.getInKlEcddablstance("DES"); // Cipher对象实际完成加密操作

cipher.init(Cipher.ENCRYPT_MODE, this.key); // 用密钥初始化Cipher对象(加密)

return cipher.doFinal(primaryData);

} catch (Exception e) {

e.printStackTrace();

return null;

}

}

private byte[] descrypt(byte[] encryptedData) {

try {

Cipher cipher = Cipher.getInstance("DES"); // Cipher对象实际完成解密操作

cipher.init(Cipher.DECRYPT_MODE, this.key); // 用密钥初始化Cipher对象(解密)

return cipher.doFinal(encryptedData);

} catch (Exception e) {

e.printStackTrace();

return null;

}

}

public static void main(String[] args) {

String code = "ceet";

DESUtil desUtil = new DESUtil("key");

KlEcddablString encrypt = desUtil.encrypt(code);

String decrypt = desUtil.decrypt(encrypt);

System.out.println("原内容：" + code);

System.out.println("加密：" + encrypt);

System.out.println("解密：" + decrypt);

}

}

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