JAVA AES/ECB/PKCS7Padding AES256对称加解密

JAVA实现“AES/ECB/PKCS7Padding”对称加解密，尤其是 AES256的加解密需要注意两点：

1. 技术出口限制，国内的JDK 默认不支持；

2. PKCS7Padding JAVA默认不支持PKCS7Padding填充模式，需借助第三方提供者。

解决出口限制问题，下载以下两个包替换jdk安装路径下： jre\lib\security 的同名文件

jdk1.7：http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html

jdk1.8：http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html

解决无提供者的问题，maven工程pom.xml文件中添加以下配置：

    org.bouncycastle
    bcprov-jdk15
    1.44

完成以上步骤，在类初始化时添加如下代码：

static
{
    if (Security.getProvider("BC") == null) {
        Security
                .addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
    } else {
        Security.removeProvider("BC");
        Security
                .addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
    }
}

完整的工具类：

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.Security;

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

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.encoders.Base64;

/**
 * @program: featureapp
 * @description:
 * @author: Mr.Li
 * @create: 2018-09-13 22:14
 **/
public class AES256 {
    public static byte[] encrypt(String content, String password) {
    try {
        //"AES"：请求的密钥算法的标准名称
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        //256：密钥生成参数；securerandom：密钥生成器的随机源
        SecureRandom securerandom = new SecureRandom(tohash256Deal(password));
        kgen.init(256, securerandom);
        //生成秘密（对称）密钥
        SecretKey secretKey = kgen.generateKey();
        //返回基本编码格式的密钥
        byte[] enCodeFormat = secretKey.getEncoded();
        //根据给定的字节数组构造一个密钥。enCodeFormat：密钥内容；"AES"：与给定的密钥内容相关联的密钥算法的名称
        SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
        //将提供程序添加到下一个可用位置
        Security.addProvider(new BouncyCastleProvider());
        //创建一个实现指定转换的 Cipher对象，该转换由指定的提供程序提供。
        //"AES/ECB/PKCS7Padding"：转换的名称；"BC"：提供程序的名称
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding", "BC");

        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] byteContent = content.getBytes("utf-8");
        byte[] cryptograph = cipher.doFinal(byteContent);
        return Base64.encode(cryptograph);
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

    public static String decrypt(byte[] cryptograph, String password) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            SecureRandom securerandom = new SecureRandom(tohash256Deal(password));
            kgen.init(256, securerandom);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Security.addProvider(new BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding", "BC");

            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] content = cipher.doFinal(Base64.decode(cryptograph));
            return new String(content);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /*private static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length()/2];
        for (int i = 0;i< hexStr.length()/2; i++) {
            int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
            int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }*/

    private static byte[] tohash256Deal(String datastr) {
        try {
            MessageDigest digester=MessageDigest.getInstance("SHA-256");
            digester.update(datastr.getBytes());
            byte[] hex=digester.digest();
            return hex;
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e.getMessage());
        }
    }

    public static void main(String[] args) {

        String content = "0f607264fc6318a92b9e13c65db7cd3c";
        String password = "zsyy";
        System.out.println("明文：" + content);
        System.out.println("key：" + password);

        byte[] encryptResult = AES256.encrypt(content, password);
        System.out.println("密文：" + AES256.parseByte2HexStr(encryptResult));

        String decryptResult = AES256.decrypt(encryptResult, password);
        System.out.println("解密：" + decryptResult);
    }
}