java实现基于PKCS7Padding填充方式的AES加解密

<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk15on</artifactId>
<version>1.47</version>
</dependency>

import java.security.Security;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class AESpkcs7paddingUtil {

/**
* 密钥算法
*/
private static final String KEY_ALGORITHM = "AES";

/**
* 加密/解密算法 / 工作模式 / 填充方式
* Java 6支持PKCS5Padding填充方式
* Bouncy Castle支持PKCS7Padding填充方式
*/
private static final String CIPHER_ALGORITHM = "AES/ECB/PKCS7Padding";

static {
//如果是PKCS7Padding填充方式，则必须加上下面这行
Security.addProvider(new BouncyCastleProvider());
}

/**
* 生成密钥
* @return	密钥
* @throws Exception
*/
public static String generateKey() throws Exception {
//实例化密钥生成器
KeyGenerator kg = KeyGenerator.getInstance(KEY_ALGORITHM);
/**
* 设置AES密钥长度
* AES要求密钥长度为128位或192位或256位，java默认限制AES密钥长度最多128位
* 如需192位或256位，则需要到oracle官网找到对应版本的jdk下载页，在"Additional Resources"中找到
* "Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files",点击[DOWNLOAD]下载
* 将下载后的local_policy.jar和US_export_policy.jar放到jdk安装目录下的jre/lib/security/目录下，替换该目录下的同名文件
*/
kg.init(128);
//生成密钥
SecretKey secretKey = kg.generateKey();
//获得密钥的字符串形式
return Base64.encodeBase64String(secretKey.getEncoded());
}

/**
* AES加密
* @param source	源字符串
* @param key	密钥
* @return	加密后的密文
* @throws Exception
*/
public static String encrypt(String source, String key) throws Exception {
byte[] sourceBytes = source.getBytes("UTF-8");
byte[] keyBytes = Base64.decodeBase64(key);
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM, "BC");
cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, KEY_ALGORITHM));
byte[] decrypted = cipher.doFinal(sourceBytes);
return Base64.encodeBase64String(decrypted);
}

/**
* AES解密
* @param encryptStr	加密后的密文
* @param key	密钥
* @return	源字符串
* @throws Exception
*/
public static String decrypt(String encryptStr, String key) throws Exception {
byte[] sourceBytes = Base64.decodeBase64(encryptStr);
byte[] keyBytes = Base64.decodeBase64(key);
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM, "BC");
cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(keyBytes, KEY_ALGORITHM));
byte[] decoded = cipher.doFinal(sourceBytes);
return new String(decoded, "UTF-8");
}

}