关于 aes 算法的使用问题

网上找的一段代码，用这代码的进行测试，生成的结果到好几个 aes 在线加密网站上去测试，测试结果都不对，麻烦请教下这段 aes 工具类代码有错吗？

第二个就是如果秘钥长度用 256 位的，这样设置 kg.init(256, new SecureRandom(key.getBytes()));和 kg.init(128, new SecureRandom(key.getBytes()));结果是一样的是怎么回事额。

import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.spec.SecretKeySpec; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import java.util.logging.Level; import java.util.logging.Logger;

public class AESUtil2 {

private static final String KEY_ALGORITHM = "AES";
private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";//默认的加密算法

/**
 * AES 加密操作
 *
 * @param content 待加密内容
 * @param key 加密密钥
 * @return 返回 Base64 转码后的加密数据
 */
public static String encrypt(String content, String key) {
    try {
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器

        byte[] byteContent = content.getBytes("utf-8");

        cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));// 初始化为加密模式的密码器

        byte[] result = cipher.doFinal(byteContent);// 加密

        return java.util.Base64.getEncoder().encodeToString(result);//通过 Base64 转码返回

    } catch (Exception ex) {
        Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
    }

    return null;
}

/**
 * AES 解密操作
 *
 * @param content
 * @param key
 * @return
 */
public static String decrypt(String content, String key) {

    try {
        //实例化
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

        //使用密钥初始化，设置为解密模式
        cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));

        //执行操作
        byte[] result = cipher.doFinal(java.util.Base64.getDecoder().decode(content));


        return new String(result, "utf-8");
    } catch (Exception ex) {
        Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
    }

    return null;
}

/**
 * 生成加密秘钥
 *
 * @return
 */
private static SecretKeySpec getSecretKey(final String key) {
    //返回生成指定算法密钥生成器的 KeyGenerator 对象
    KeyGenerator kg = null;

    try {
        kg = KeyGenerator.getInstance(KEY_ALGORITHM);

        //AES 要求密钥长度为 128
        kg.init(128, new SecureRandom(key.getBytes()));

        //生成一个密钥
        SecretKey secretKey = kg.generateKey();

        return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为 AES 专用密钥
    } catch (NoSuchAlgorithmException ex) {
        Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
    }

    return null;
}

public static void main(String[] args) {
    String content = "hello world";
    String key = "password";
    System.out.println("content:" + content);
    String s1 = AESUtil.encrypt(content, key);
    System.out.println("s1:" + s1);
    System.out.println("s2:"+AESUtil.decrypt(s1, key));
    //content:hello world
    //s1:xvhDfp2GjtmdjK2PbEF4WA==
    //s2:hello world
}

}

louislivi

2020-05-26 15:18:22 +08:00

```java
public class AESUtil {

private static final String KEY_ALGORITHM = "AES";
//默认的加密算法
private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";

private static String key = "1H5c65423RR23VcYdFdCGcpLlNGvUNvdM8yUNJb0809";

/**
* AES 加密操作
*
* @param content 待加密内容
* @return 返回 Base64 转码后的加密数据
*/
public static String encrypt(String content) {
try {
// 创建密码器
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

byte[] byteContent = content.getBytes("utf-8");
// 初始化为加密模式的密码器
cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));
// 加密
byte[] result = cipher.doFinal(byteContent);
//通过 Base64 转码返回
return new String(Base64.encodeBase64(result));

} catch (Exception ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}

return null;
}

/**
* AES 解密操作
*
* @param content
* @return
*/
public static String decrypt(String content) {
try {
//实例化
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
//使用密钥初始化，设置为解密模式
cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));
//执行操作
byte[] result = cipher.doFinal(Base64.decodeBase64(content));
return new String(result, "utf-8");
} catch (Exception ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}

/**
* 生成加密秘钥
*
* @return
*/
private static SecretKeySpec getSecretKey(final String key) {
//返回生成指定算法密钥生成器的 KeyGenerator 对象
KeyGenerator kg = null;

try {
kg = KeyGenerator.getInstance(KEY_ALGORITHM);
//AES 要求密钥长度为 128
SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
secureRandom.setSeed(key.getBytes("utf-8"));
kg.init(128, secureRandom);

//生成一个密钥
SecretKey secretKey = kg.generateKey();
// 转换为 AES 专用密钥
return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);
} catch (NoSuchAlgorithmException | UnsupportedEncodingException ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}

return null;
}
```