[原创][原创]M30A1_FW110B02固件解密，AES、EVP-ByTokey(SHA-256)-茶余饭后-看雪安全社区

[原创][原创]M30A1_FW110B02固件解密，AES、EVP-ByTokey(SHA-256)

发表于: 2025-12-14 21:40 219

[原创][原创]M30A1_FW110B02固件解密，AES、EVP-ByTokey(SHA-256)

朝阳Sec

2025-12-14 21:40

219

1、信息收集

编辑

我们拿到M30A1的110版本先binwalk看一下，里面只有一个0x41的OpenSSL 加密，salted，并且盐也给我们了。

6dfK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

能确定是加密态，熵值接近1。

10eK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

这里发现了Salt

2、加盐算法

我们在了解是OpenSSL加密那就先去了解一下他的加密逻辑。

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
65            0x41            OpenSSL encryption, salted, salt: 0xE5C9BB84466AF3C5

f11K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

这里有三个参数，65是一个10进制的数，标识加密部分在文件中的起始位置

0x41是16进制表示，与65相同

下面的是加密的描述

OpenSSL encryption, salted, salt:0xE5C9BB84466AF3C5
OpenSSL encryption:表示文件这一部分用了OpenSSL工具加密
salted:表示加密过程中使用的盐值。
salt：提供了盐的具体值，即0xE5C9BB84466AF3C5
这个盐是生成密钥的一部分。

487K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

3、核心引擎AES-128 Encryption

e21K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

我们能找到1.02版本是AES-128加密，而且在更新的版本更新公告中也没发现其他的安全升级。

AES

AES-128是对称加密的，意味着加密解密都是同样的一把钥匙(Key)，我们需要扣出这个Key

这里的128含义是密钥(Key)长度为128位，也就是16字节(128 ÷ 8),换算成Hex字符串是32个字符。

CBC

AES不会把整个文件一口气加密，把文件切成一块一块的,每块16字节处理，但是问题在于如果只是每块独立加密，ECB模式，那么文件里相同的的内容，加密后还是相同的密文，能看得出来特征。

如果解决就引用了CBC模式，他是连锁反应，第二块加密依赖于第一块结果，第三块，依赖第二块加密结果，以此类推，但是第一块加密需要依赖的就是IV，也就是初始化向量这样一个概念来作为加密引擎。

填充

AES的块大小固定是16字节，如果文件大小不是16的倍数会用到OpenSSL的默认填充方式，他会在文件末尾补上几个字节，凑齐16的倍数，解密把他们丢掉。

加密逻辑

OpenSSL是一个工具库，他在加密有两种方案

(1)、基于密码加密

输入端：我们只需要一个密码(Password)和一个Salt(盐)

过程：

1、OpenSSL使用KDF（密钥派生函数，如MD5或PBKDF2）混合密码和Salt

2、算出一个Key/IV

3、用算出来的Key/IV去跑AES

文件特征：文件头通常有Salted__字样，后面跟着8字节的盐

(2)、基于原始密钥(Raw Key/iv)

输入端：直接给AES引擎塞入Key(16字节)和IV(16字节)

过程：跳过派生，直接加密

文件特征：

Key:通常硬编码在解密程序(如u-boot或解密脚本)，文件找不到

IV:通常放在文件头部的某个固定位置，比如前16字节，或偏移0x20处，因此解密必须用到。

总结

我们回归D-Link固件想要破解，就必须填上三个空

1、Key

一个16字节的Hex串，一般藏在路由器上个版本系统文件里，或者写死在解密程序的二进制代码里，但对于D-Link这个是通用。

2、IV（初始化向量）

16字节，他一定在固件文件里，因为解密程序运行时第一件事就是读取文件头的IV

3、算法

加密方式，我们能确定是AES-128-CBC

4、追踪IV、Key、确定密文长度、文件头分析。

那我们这一套非常之明确了，这就是第一种玩法嘛，非常明显的Salt__后的8字节，我们提取出来，然后还有一个点就是确定密文长度。我们一步一步来，先来最简单的确定密文长度。

一、头部元数据校验(确定加密长度)

由于在1.20版本中的一些发现，这个未加密的文件头中会有加密长度，我们寻找一下。

fadK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

非常明显的一点就是0x50之前都是明文，以0x50作为一个分界线，我们可以在这个文件头中找到这个加密长度，或者从0x50开始往后截取成一个新的文件。我们先看一下整个文件大小。

af6K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

我们先查询到整个文件的长度，这个作用是比对长度，以此为标准，因为明文占用的空间非常的小，大部分都是加密的，因此我们找那串16进制的符合。

bd3K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

我们写了一个脚本。我们先把猜测的加密部分提取出来，比对一下大小。

353K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

这里应该是截的有些偏差，不过大概能判断出这两个位置是加密长度，因为去除头部明文差不多是这个长度。

我们应该从0x51开始截取，我们再截一次。

 dd if=M30A1_FW110B02.bin bs=1 skip=80 of=payload_80.bin

66bK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

b97K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

好像区别不大。

但我们在提起盐的部分发现从0x41(salt+加密长度)开始截取的长度刚好就是38871424，那么我们找的文件长度是没问题的，剔除salt就是整个加密长度。

二、提取Salt

我们一开始使用的binwalk很明显的发现了0X41开始就是Salt__，然后后面8字节是salt值。

我们先把这个salt提取出来。

ENCSIZE=$(hexdump -s 0x18 -n 4 -e '1/4 "%u\n"' M30A1_FW110B02.bin)
echo "ENCSIZE=$ENCSIZE"
ENCSIZE=38871424
dd if=M30A1_FW110B02.bin of=raw_enc.bin bs=1 skip=$((0x41)) count=$ENCSIZE

8ccK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

我们先提取盐和加密数据这一段，从0x41开始。

0f0K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

这次就是对的，也符合我们一开始用binwalk找到的salt: 0xE5C9BB84466AF3C5。

//从第 73 字节 (0x49) 开始，切 8 个字节，存为 salt.bin
dd if=salt+ciphertext.bin bs=1 skip=8 count=8 of=salt.bin
//查看提取出来的 Salt (HEX 格式)
xxd -p salt.bin

b9cK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

1f7K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

确定这是我们的salt，接下来寻找IV。

dd if=salt+ciphertext.bin bs=1 skip=16 of=ciphertext.bin

a38K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

三、寻找IV

首先我们理清一下逻辑，我们再看一遍这两种方法，一种是基于密码加密、一种是基于原始密钥，我们有Key，Salt那就可以尝试基于原始密钥的方式了，去寻找IV尝试解密，我们直接给AES塞入Key和IV直接加密，由此我们大概率能猜到IV。

b2dK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

为什么说IV我们可以找到，我们可以确认算法是AES-128,这是在升级公告中所提到的，IV长度需求是16字节，我们紧盯着0x41之前的数据。

cafK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

Salt之前的数据，前32字节(0x00-0x1F)元数据区，这里存放着魔术头、固件大小、校验和版本号等，元数据结束后紧接着通常是加密参数，我们最重要的就是IV，然后0x41又是Salt，这是OpenSSL的标准头，其实我们要找的IV必须存在0x20-0x40这一段空窗期，不然我们没办法在解密前拿到他，是这样的。

接下来我们分析这一段吧，把他了解透彻。

MH01就是固件的签名，魔术头，01应该代表版本号v1，然后0x10这一行也有一个MH01再次确认一遍，0x18是我们大概是加密数据的长度。然后再往后走就发现了两行奇怪的数据，我们看一下。

7edK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

这两行看到了奇怪的数据，那我们根据之前的想法也大概率能想到是IV，这32的ASCII字符表示16字节的HEX IV。

为什么这32字节是16位的IV呢，因为AES算法在底层运算时是需要16字节的二进制数据的，我们开始截取。

(1)、提取

我们提取就要从0x20开始，也就是32字节开始，切32字节，把IV保存成一个文件

(2)、确认IV

如果这段数据是IV的字符串表示，他应该只包含0-9和a-f(或A-F)字符，他不会出现乱码，我们可以试试cat和hendump验证验证。

c4fK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

我们大概率可以确认是IV

256K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

接下来验证一下字符个数，也就是长度。

62dK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

5、尝试解密

既然我们知道他是用OpenSSL加密的，我们尝试用OpenSSL解密，我们调用OpenSSL的enc，尝试一下。

aes-128-cbc：指定算法，告诉这个OpenSSL是AES加密，128位的，CBC模式。

-D：Decrypt(解密)不加这个是默认加密

-K：Key(密钥)通用钥是

-iv(小写)：切出来的IV

-in：输入文件(纯密文)

-out：输出文件(解开后的固件)

openssl aes-128-cbc -d -K xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx -iv $(cat IV.txt) -in clean_ciphertext.bin -out decrypted_b451.bin

d86K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

这里尝试了很多次，好像都不太行

f2cK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

有一些突破，但是不知道是不是这样。

0bcK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

偶然回头以看发现我们已经成功破解了，我们回顾一下解密这一部分。但是写到这里我整个人还是有点疑惑，疑惑在于不论我是否解密成功他都会报错

6、解密回顾

一、提取加密字段、IV

echo xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx > IV.txt
写入IV

fddK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

精确提取从Salted__头部开始的完整加密数据块

 dd if=M30A1_FW110B02.bin of=raw_enc.bin bs=1 skip=65

9e8K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

但是有时候拆分数据时候会发生错误，建议用dd来截取。

我们可以把签名这一段忽略

376K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

这里面我们把0x41开始截取，这样我们能得到一个带盐+密文的字段，然后后续我们再提盐。

8cbK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

提取到这样我们整个文件就工整很多了，然后我们提取后8位的Salt，然后再把整个Salt部分去除掉就变成了完整的加密部分。

二、核心解密

下一步我们就用OpenSSL解密，我们一开始手上是掌握了Key的，然后使用命令。

openssl aes-128-cbc -d -pass pass:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx -in raw_enc.bin -out try_pass_mode.bin

7c6K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

三、密码学模式推断与试错

首先确定了密文的起始字节为Salted__，证实用了OpenSSL的EVP框架，Key派生是必须的。

然后基于D-Link更新公告和IV长度，锁定算法为AES-128-CBC

四、KDF(密钥派生成功)

改变Key的角色，激活OpenSSL的自动派生机制

运行-pass模式，将Key是为Password,结果就是OpenSSL自动读取文件中的Salt，并使用Password+Salt派生出Key/IV，然后我们成功实现了，熵值降到0.69，证明Key是Password,而bad decrypt是虚假报错，数据主体已解密。

五、EVP_BytesTokey派生逻辑实现

#!/bin/bash

# --- 1. 定义常量 ---
PASSWORD="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
# 假设 salt 已经从 raw_enc.bin 中提取并保存在这个文件里
SALT_FILE="extracted_salt.bin" 

# --- 2. KDF 第一轮：生成 D1 ---
echo "--- KDF 1/2: 生成 D1 (SHA256(Password + Salt)) ---"
# 拼接 Password 和 Salt，并计算 SHA256 摘要
{ printf "%s" "$PASSWORD"; cat "$SALT_FILE"; } | openssl dgst -sha256 -binary > D1.bin
echo "D1.bin 创建完成 (32 bytes)"

# --- 3. KDF 第二轮：生成 D2 ---
echo -e "\n--- KDF 2/2: 生成 D2 (SHA256(D1 + Password + Salt)) ---"
# 拼接 D1.bin、Password 和 Salt，并计算 SHA256 摘要
{ cat D1.bin; printf "%s" "$PASSWORD"; cat "$SALT_FILE"; } | openssl dgst -sha256 -binary > D2.bin
echo "D2.bin 创建完成 (32 bytes)"

# --- 4. 拼接并提取 Key/IV ---
echo -e "\n--- 提取 Key 和 IV ---"
# 将 D1 和 D2 拼接成完整的 64 字节密钥材料
cat D1.bin D2.bin > KM.bin

# 提取 Key (前 16 字节用于 AES-128)
dd if=KM.bin of=derived_key.bin bs=1 count=16 status=none

# 提取 IV (从 16 字节开始，提取 16 字节)
dd if=KM.bin of=derived_iv.bin bs=1 skip=16 count=16 status=none

# --- 5. 打印结果 (十六进制) ---
echo -e "\n派生出的 Key 和 IV (十六进制):"
KEY_HEX=$(xxd -p derived_key.bin | tr -d '\n')
IV_HEX=$(xxd -p derived_iv.bin | tr -d '\n')

echo "KEY (-K): $KEY_HEX"
echo "IV (-iv): $IV_HEX"

# --- 6. 最终解密命令示例 ---
# 使用派生出的 Key 和 IV，对纯密文文件 (cipher.bin) 进行解密
# openssl aes-128-cbc -d -K $KEY_HEX -iv $IV_HEX -in cipher.bin -out manual_code_decrypt.bin

7a6K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

六、解密实质

一开始的Key我们原以为是用于解密也就是-K模式，然后呗KDF流程处理了，但是这个Key是作为KDF的输入，也就是-Pass模式，他被OpenSSL读取，然后与Salt混合，派生出了真的AES Key和IV。

也就是说我们提供的Hex串作为Pasword,必须进入KDF与Salt混合，才能产生出真的Key和IV

七、手动解密流程

如果我们想脱离OpenSSL的-pass模式，我们需要以下三个步骤。

（1）、定义常量

 PASSWORD="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" 
 SALT_FILE="extracted_salt.bin"

6cfK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

我们需要把Key当作Password，然后把Salt单独放一个文件中。

（2）、运行KDF逻辑，生成Key

这里使用SHA-256两轮KDF逻辑，只提取key

D1 = SHA256({Password}+{Salt})

//生成D1(SHA256(Password + Salt))
{ printf "%s" "$PASSWORD"; cat "$SALT_FILE"; } | openssl dgst -sha256 -binary > D1.bin

ac1K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

D2 = (SHA256(D1 + Password + Salt))

//生成 D2 (SHA256(D1 + Password + Salt)) { cat D1.bin; printf"%s""$PASSWORD"; cat "$SALT_FILE"; } | openssl dgst -sha256 -binary > D2.bin

88cK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

拼接并提取Key（前16字节）

 cat D1.bin D2.bin > KM.bin 
 dd if=KM.bin of=derived_key.bin bs=1 count=16 status=none

17aK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

# 将 Key 转换为十六进制字符串 
KEY_HEX=$(xxd -p derived_key.bin | tr -d '\n') echo"Derived Key: $KEY_HEX"

afcK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

（3）、混合解密(Code Mode)

现在用我们派生出的Key和Header中的IV对纯密文解密。

openssl aes-128-cbc -d \
    -K "$KEY_HEX" \
    -iv "$IV_HEX" \
    -in cipher.bin \
    -out hybrid_decrypt.bin

927K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

我们可以得到派生的Key和IV。

openssl aes-128-cbc -d -K xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx -iv xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx -in cipher.bin -out manual_decrypt_success.bin

bbbK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

然后再执行即可。

16bK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

这里我们想不依赖-pass模式，手动解密，把Key当作Password然后追踪一下全流程，这样来说说可以更清晰的其加密过程。

echo "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" | xxd -r -p > password_raw.bin
//准备好Key也就是Password
echo "E5C9BB84466AF3C5" | xxd -r -p > salt_raw.bin
//盐

{ cat password_raw.bin; cat salt_raw.bin; } | openssl dgst -sha256 -binary > D1.bin
//生成D1

echo -n "D1 (HEX): " && xxd -p D1.bin | tr -d '\n' && echo ""
//打印D1

D1：
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx


{ cat D1.bin; cat password_raw.bin; cat salt_raw.bin; } | openssl dgst -sha256 -binary > D2.bin
//生成D2

echo -n "D2 (HEX): " && xxd -p D2.bin | tr -d '\n' && echo ""
//打印D2
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

cat D1.bin D2.bin > KM.bin
//拼接完整密钥

dd if=KM.bin of=derived_key.bin bs=1 count=16 status=none
//提取Key前16字节

dd if=KM.bin of=derived_iv.bin bs=1 skip=16 count=16 status=none
//提取Key后16字节

echo -n "派生 Key: " && xxd -p derived_key.bin | tr -d '\n' && echo ""
# 10. 打印派生的 Key (D1)

# 11. 打印派生的 IV (D1)
echo -n "派生 IV: " && xxd -p derived_iv.bin | tr -d '\n' && echo ""

cfeK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">

31dK9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

成功

八、算法原理(IV和Key来源)

为什么是SHA-256哈希运算，因为每次运行SHA-256都能产出32字节的数据。

但是问题在于我们在文件头看到了数据只有IV没见到Key的身影，原因就在于如果只进行一轮的话确实刚好足够32字节，但这样Key和IV必须从这同一个32字节中分出来。

但是如果Key和IV都是同一轮生产出的话会很不安全，基本是打名牌，最安全的方式就是第一次产出32字节提供给Key，第二次产出提供给IV，这样总结64字节，也会很安全。因此厂商必须进行两次SHA-256运算，才能保证Key和IV都有足够的密钥数据，这是更安全的。

790K9s2c8@1M7s2y4Q4x3@1q4Q4x3V1k6Q4x3V1k6U0M7$3c8F1K9h3#2Y4i4K6u0W2j5$3&6Q4x3V1k6J5k6h3I4W2j5i4y4W2i4K6u0r3j5X3I4G2k6#2)9#2k6X3g2V1K9i4c8G2M7W2)9#2k6X3S2@1L8h3I4Q4x3V1k6J5k6h3I4W2j5i4y4W2x3W2)9J5k6e0c8Q4x3X3f1@1i4K6u0r3j5$3E0W2k6r3W2@1L8%4u0Q4x3V1k6H3L8s2g2Y4K9h3&6K6i4K6u0r3N6$3W2V1k6$3g2@1i4K6u0r3K9h3#2S2k6$3g2K6i4K6u0r3K9r3q4F1k6r3I4W2i4K6u0W2M7r3&6Y4i4K6t1&6i4K6y4n7">编辑

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