web安全学习笔记【09】——算法2

基础[1] 入门-算法逆向&散列对称非对称&JS源码逆向&AES&DES&RSA&SHA

演示案例：

算法加密-概念&分类&类型
加密解密-识别特征&解密条件
解密实例-密文存储&数据传输

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| 安全测试中：密文-有源码直接看源码分析算法（后端必须要有源码才能彻底知道）密文-没有源码1、猜识别 2、看前端JS（加密逻辑是不是在前端） #### #算法加密-概念&分类&类型 1. 单向散列加密 -MD5 单向散列加密算法的优点有(以MD5为例)：方便存储，损耗低：加密/加密对于性能的损耗微乎其微。单向散列加密的缺点就是存在暴力破解的可能性，最好通过加盐值的方式提高安全性，此外可能存在散列冲突。我们都知道MD5加密也是可以破解的。常见的单向散列加密算法有： MD5 SHA MAC CRC 2. 对称加密 -AES 对称加密优点是算法公开、计算量小、加密速度快、加密效率高。缺点是发送方和接收方必须商定好密钥，然后使双方都能保存好密钥，密钥管理成为双方的负担。常见的对称加密算法有： DES AES RC4 3. 非对称加密 -RSA 非对称加密的优点是与对称加密相比，安全性更好，加解密需要不同的密钥，公钥和私钥都可进行相互的加解密。缺点是加密和解密花费时间长、速度慢，只适合对少量数据进行加密。常见的非对称加密算法： RSA RSA2 PKCS #### #加密解密-识别特征&解密条件 MD5密文特点： 1、由数字"0-9"和字母"a-f"所组成的字符串 2、固定的位数 16 和 32位解密需求：密文即可，但复杂明文可能解不出 BASE64编码特点： 0、大小写区分，通过数字和字母的组合 1、一般情况下密文尾部都会有两个等号，明文很少的时候则没有 2、明文越长密文越长，一般不会出现"/""+"在密文中 AES、DES密文特点：同BASE64基本类似，但一般会出现"/"和"+"在密文中解密需求：密文，模式，加密Key，偏移量，条件满足才可解出 RSA密文特点：特征同AES,DES相似，但是长度较长解密需求：密文，公钥或私钥即可解出 > > > AES加密主要在于Key值 > > DES加密主要是Key和iv值，即密码和偏移量 > > 非对称加密RSA 公钥私钥 > 解密方式：如果对方用公钥加密，只有私钥也能解密，但用公钥无法解密 > 如果对方用私钥加密，只有公钥也能解密，但用私钥无法解密 > > 其他密文特点见： 1.30余种加密编码类型的密文特征分析（建议收藏） https://mp.weixin.qq.com/s?__biz=MzAwNDcxMjI2MA==\&mid=2247484455\&idx=1\&sn=e1b4324ddcf7d6123be30d9a5613e17b\&chksm=9b26f60cac517f1a920cf3b73b3212a645aeef78882c47957b9f3c2135cb7ce051c73fe77bb2\&mpshare=1\&scene=23\&srcid=1111auAYWmr1N0NAs9Wp2hGz\&sharer_sharetime=1605145141579\&sharer_shareid=5051b3eddbbe2cb698aedf9452370026#rd 2.CTF中常见密码题解密网站总结（建议收藏） https://blog.csdn.net/qq_41638851/article/details/100526839 3.CTF密码学常见加密解密总结（建议收藏） https://blog.csdn.net/qq_40837276/article/details/83080460 #### #解密实例-密文存储&数据传输 1、密码存储（后端处理） X3.2-md5&salt DZ对应代码段-/uc_server/model/user.php function add_user() { $password = md5(md5($ password).$salt); } <?PHP $h = 'd7192407bb4bfc83d28f374b6812fbcd'; $hash=md5(md5('123456').'3946d5'); if($ h==$hash){ echo 'ok'; }else{ echo 'no'; } ?> X3.5-hash DZ对应代码段-/uc_server/model/user.php function add_user() { $salt = ''; $password = $this-\>generate_password($ password); } function generate_password($password) { $algo = $this->get_passwordalgo(); $options = $this->get_passwordoptions(); $hash = password_hash($ password, $algo, $options); } <?PHP $hash = '$2y $10$ KA.7VYVheqod8F3X65tWjO3ZXfozNA2fC4oIZoDSu/TbfgKmiw7xO'; if (password_verify('123456', $hash)) { echo 'ok'; } else { echo 'error'; } ?> 2、数据通讯 -博客登录-zblog（前端处理） <script src="script/md5.js" type="text/javascript"></script> $("#btnPost").click(function(){ var strPassWord=$ ("#edtPassWord").val(); $("form").attr("action","cmd.php?act=verify"); $("#password").val(MD5(strPassWord)); -墨者靶场-（后端处理） -1 union select 1,database(),user(),4_mozhe xgd58ipTrnx8VzSBJicqCibZxIRsZKgXOYUrNQP8fCCtx9JZ+6K1hHt7RKkzV305 eGdkNThpcFRybng4VnpTQkppY3FDaWJaeElSc1pLZ1hPWVVyTlFQOGZDQ3R4OUpaKzZLMWhIdDdSS2t6VjMwNQ== |

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| //PHP7.3加密演示代码块 <?php //aes namespace vendor; class EncryptionTool{ public static function enAES($originTxt, $key): string{ return base64_encode(openssl_encrypt($ originTxt, 'AES-128-ECB', $key, OPENSSL_RAW_DATA)); } public static function deAES($ originTxt, $key): string{ $data = base64_decode($ originTxt); return openssl_decrypt( $data,'AES-128-ECB',$ key, OPENSSL_RAW_DATA); } } //des class DES { /** * @var string $method 加解密方法，可通过 openssl_get_cipher_methods() 获得 */ protected $method; /** * @var string $key 加解密的密钥 */ protected $key; /** * @var string $output 输出格式无、base64、hex */ protected $output; /** * @var string $iv 加解密的向量 */ protected $iv; /** * @var string $options */ protected $options; // output 的类型 const OUTPUT_NULL = ''; const OUTPUT_BASE64 = 'base64'; const OUTPUT_HEX = 'hex'; /** * DES constructor. * @param string $key * @param string $method \* ECB DES-ECB、DES-EDE3 （为 ECB 模式时，$ iv 为空即可） * CBC DES-CBC、DES-EDE3-CBC、DESX-CBC * CFB DES-CFB8、DES-EDE3-CFB8 * CTR * OFB * * @param string $output * base64、hex * * @param string $iv * @param int $options \*/ public function __construct($ key, $method = 'DES-ECB', $output = '', $iv = '', $options = OPENSSL_RAW_DATA | OPENSSL_NO_PADDING) { $this->key = $key; $this->method = $method; $this->output = $output; $this->iv = $iv; $this->options = $options; } /** * 加密 * * @param $str \* @return string \*/ public function encrypt($ str) { $str = $this-\>pkcsPadding($ str, 8); $sign = openssl_encrypt($ str, $this->method, $this->key, $this->options, $this-\>iv); if ($ this->output == self::OUTPUT_BASE64) { $sign = base64_encode($ sign); } else if ($this->output == self::OUTPUT_HEX) { $sign = bin2hex($ sign); } return $sign; } /** * 解密 * * @param $encrypted \* @return string \*/ public function decrypt($ encrypted) { if ($this->output == self::OUTPUT_BASE64) { $encrypted = base64_decode($ encrypted); } else if ($this->output == self::OUTPUT_HEX) { $encrypted = hex2bin($ encrypted); } $sign = @openssl_decrypt($ encrypted, $this->method, $this->key, $this->options, $this->iv); $sign = $this-\>unPkcsPadding($ sign); $sign = rtrim($ sign); return $sign; } /** * 填充 * * @param $str * @param $blocksize \* @return string \*/ private function pkcsPadding($ str, $blocksize) { $pad = $blocksize - (strlen($ str) % $blocksize); return $str . str_repeat(chr($ pad), $pad); } /** * 去填充 * * @param $str \* @return string \*/ private function unPkcsPadding($ str) { $pad = ord($ str{strlen( $str) - 1}); if ($ pad > strlen( $str)) { return false; } return substr($ str, 0, -1 * $pad); } } //rsa define('RSA_PUBLIC', '-----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCmkANmC849IOntYQQdSgLvMMGm 8V/u838ATHaoZwvweoYyd+/7Wx+bx5bdktJb46YbqS1vz3VRdXsyJIWhpNcmtKhY inwcl83aLtzJeKsznppqMyAIseaKIeAm6tT8uttNkr2zOymL/PbMpByTQeEFlyy1 poLBwrol0F4USc+owwIDAQAB -----END PUBLIC KEY-----'); define('RSA_PRIVATE','-----BEGIN PRIVATE KEY----- MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAKaQA2YLzj0g6e1h BB1KAu8wwabxX+7zfwBMdqhnC/B6hjJ37/tbH5vHlt2S0lvjphupLW/PdVF1ezIk haGk1ya0qFiKfByXzdou3Ml4qzOemmozIAix5ooh4Cbq1Py6202SvbM7KYv89syk HJNB4QWXLLWmgsHCuiXQXhRJz6jDAgMBAAECgYAIF5cSriAm+CJlVgFNKvtZg5Tk 93UhttLEwPJC3D7IQCuk6A7Qt2yhtOCvgyKVNEotrdp3RCz++CY0GXIkmE2bj7i0 fv5vT3kWvO9nImGhTBH6QlFDxc9+p3ukwsonnCshkSV9gmH5NB/yFoH1m8tck2Gm BXDj+bBGUoKGWtQ7gQJBANR/jd5ZKf6unLsgpFUS/kNBgUa+EhVg2tfr9OMioWDv MSqzG/sARQ2AbO00ytpkbAKxxKkObPYsn47MWsf5970CQQDIqRiGmCY5QDAaejW4 HbOcsSovoxTqu1scGc3Qd6GYvLHujKDoubZdXCVOYQUMEnCD5j7kdNxPbVzdzXll 9+p/AkEAu/34iXwCbgEWQWp4V5dNAD0kXGxs3SLpmNpztLn/YR1bNvZry5wKew5h z1zEFX+AGsYgQJu1g/goVJGvwnj/VQJAOe6f9xPsTTEb8jkAU2S323BG1rQFsPNg jY9hnWM8k2U/FbkiJ66eWPvmhWd7Vo3oUBxkYf7fMEtJuXu+JdNarwJAAwJK0YmO LxP4U+gTrj7y/j/feArDqBukSngcDFnAKu1hsc68FJ/vT5iOC6S7YpRJkp8egj5o pCcWaTO3GgC5Kg== -----END PRIVATE KEY-----'); $password='xiaodisec'; #### //md5 echo "原始数据:$ password". "<br/>"; echo "MD5加密后:".md5( $password). "\$

"; #### //base64 echo "原始数据:password". "<br/>"; echo "BASE64编码后:".base64_encode($password). "<hr/>"; #### //aes echo "原始数据: " . $password . "<br/>";

data = EncryptionTool::enAES(

password, "1234567891234567"); echo "AES加密后: " .

data . "\"; //echo "解密后: " . EncryptionTool::deAES(

data, "1234567891234567") . "<br/>"; #### //des echo "原始数据:$password". "<br/>"; $key = 'key123456'; $iv = 'iv123456'; // DES CBC 加解密 echo 'DES CBC 加解密:';

des = new DES(

key, 'DES-CBC', DES::OUTPUT_BASE64, $iv); echo $base64Sign =

des-\>encrypt(

password); echo "<br>"; //echo

des-\>decrypt(

base64Sign); echo "<hr>"; // DES ECB 加解密 echo "原始数据:$password". "<br/>"; echo 'DES ECB 加解密:';

des = new DES(

key, 'DES-ECB', DES::OUTPUT_BASE64); echo $base64Sign =

des-\>encrypt(

password); echo "<hr>"; //echo

des-\>decrypt(

base64Sign); #### //rsa ##### //公钥加密

public_key = openssl_pkey_get_public(RSA_PUBLIC); if(!

public_key){ die('公钥不可用'); } //第一个参数是待加密的数据只能是string，第二个参数是加密后的数据,第三个参数是openssl_pkey_get_public返回的资源类型,第四个参数是填充方式

return_en = openssl_public_encrypt(

password, $crypted,

public_key); if(!

return_en){ return('加密失败,请检查RSA秘钥'); }

eb64_cry = base64_encode(

crypted); echo "RSA公钥加密数据：".$eb64_cry; echo "<br>"; ##### //私钥解密

private_key = openssl_pkey_get_private(RSA_PRIVATE); if(!

private_key){ die('私钥不可用'); }

return_de = openssl_private_decrypt(base64_decode(

eb64_cry), $decrypted,

private_key); if(!

return_de){ return('解密失败,请检查RSA秘钥'); } echo "RSA私钥解密数据:".$decrypted; echo "<hr>"; ##### //私钥加密

private_key = openssl_pkey_get_private(RSA_PRIVATE); if(!

private_key){ die('私钥不可用'); }

return_en = openssl_private_encrypt(

password, $crypted,

private_key); if(!

return_en){ return('加密失败,请检查RSA秘钥'); }

eb64_cry = base64_encode(

crypted); echo "RSA私钥加密数据".$eb64_cry; echo "<br>"; ##### //公钥解密

public_key = openssl_pkey_get_public(RSA_PUBLIC); if(!

public_key){ die('公钥不可用'); }

return_de = openssl_public_decrypt(base64_decode(

eb64_cry), $decrypted,

public_key); if(!

return_de){ return('解密失败,请检查RSA秘钥'); } echo "RSA公钥解密数据:".$decrypted; echo "<hr>"; ?> |