Kuangcp/JavaBase

package security.aes.wx;

import lombok.extern.slf4j.Slf4j;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Base64;

@Slf4j
public class WxMsgAESUtil {

    static Charset CHARSET = StandardCharsets.UTF_8;

    /**
     * 对明文进行加密.
     *
     * @param text 需要加密的明文
     * @return 加密后base64编码的字符串
     * @throws AesException aes加密失败
     */
    static String encrypt(byte[] aesKey, String text) throws AesException {
        ByteGroup byteCollector = new ByteGroup();
        byte[] textBytes = text.getBytes(CHARSET);
        // randomStr + networkBytesOrder + text + appid
        byteCollector.addBytes(textBytes);
        // ... + pad: 使用自定义的填充方式对明文进行补位填充
        byte[] padBytes = PKCS7Encoder.encode(byteCollector.size());
        byteCollector.addBytes(padBytes);

        // 获得最终的字节流, 未加密
        byte[] unencrypted = byteCollector.toBytes();

        try {
            // 设置加密模式为AES的CBC模式
            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            SecretKeySpec keySpec = new SecretKeySpec(aesKey, "AES");
            // 取密钥的前16字节作为 iv 初始化向量
            IvParameterSpec iv = new IvParameterSpec(aesKey, 0, 16);
            cipher.init(Cipher.ENCRYPT_MODE, keySpec, iv);

            // 加密
            byte[] encrypted = cipher.doFinal(unencrypted);

            // 使用BASE64对加密后的字符串进行编码
            return Base64.getEncoder().encodeToString(encrypted);
        } catch (Exception e) {
            log.error("", e);
            throw new AesException(AesException.EncryptAESError);
        }
    }

    /**
     * 对密文进行解密.
     *
     * @param text 需要解密的密文
     * @return 解密得到的明文
     * @throws AesException aes解密失败
     */
    static String decrypt(byte[] aesKey, String text) throws AesException {
        byte[] original;
        try {
            // 设置解密模式为AES的CBC模式
            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            SecretKeySpec key_spec = new SecretKeySpec(aesKey, "AES");
            IvParameterSpec iv = new IvParameterSpec(Arrays.copyOfRange(aesKey, 0, 16));
            cipher.init(Cipher.DECRYPT_MODE, key_spec, iv);

            // 使用BASE64对密文进行解码
            byte[] encrypted = Base64.getDecoder().decode(text);

            // 解密
            original = cipher.doFinal(encrypted);
        } catch (Exception e) {
            log.error("", e);
            throw new AesException(AesException.DecryptAESError);
        }

        String xmlContent;
        try {
            // 去除补位字符
            byte[] bytes = PKCS7Encoder.decode(original);
            xmlContent = new String(bytes, CHARSET);
        } catch (Exception e) {
            log.error("", e);
            throw new AesException(AesException.IllegalBuffer);
        }

        return xmlContent;
    }

}