com.seejoke.wechat.util.PKCS7Encoder Maven / Gradle / Ivy
/**
* 对公众平台发送给公众账号的消息加解密示例代码.
*
* @copyright Copyright (c) 1998-2014 Tencent Inc.
*/
// ------------------------------------------------------------------------
package com.seejoke.wechat.util;
import java.nio.charset.Charset;
import java.util.Arrays;
public class PKCS7Encoder {
private static final Charset CHARSET = Charset.forName("utf-8");
private static final int BLOCK_SIZE = 32;
public static byte[] encode(int count) {
// 计算需要填充的位数
int amountToPad = BLOCK_SIZE - (count % BLOCK_SIZE);
if (amountToPad == 0) {
amountToPad = BLOCK_SIZE;
}
// 获得补位所用的字符
char padChr = chr(amountToPad);
String tmp = new String();
for (int index = 0; index < amountToPad; index++) {
tmp += padChr;
}
return tmp.getBytes(CHARSET);
}
public static byte[] decode(byte[] decrypted) {
int pad = (int) decrypted[decrypted.length - 1];
if (pad < 1 || pad > 32) {
pad = 0;
}
return Arrays.copyOfRange(decrypted, 0, decrypted.length - pad);
}
public static char chr(int a) {
byte target = (byte) (a & 0xFF);
return (char) target;
}
}