舉個通俗易懂的例子，假設(shè)我們再登錄一個網(wǎng)站，發(fā)送賬號和密碼，請求被攔截了。 密碼沒加密，那攻擊者就直接拿到了密碼，這是最搓的。 密碼加密了，是不可逆加密，那攻擊者只需要模擬那個請求即可登錄。 密碼加密了...
舉個通俗易懂的例子，假設(shè)我們再登錄一個網(wǎng)站，發(fā)送賬號和密碼，請求被攔截了。
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密碼沒加密，那攻擊者就直接拿到了密碼，這是最搓的。
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密碼加密了，是不可逆加密，那攻擊者只需要模擬那個請求即可登錄。
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密碼加密了，是可逆加密，其中攜帶有時間等參數(shù)，后臺可以根據(jù)時間等參數(shù)來判斷是否有效，但因為是在前端加密，其加密方式也能在代碼中找到，找到加密方式就可以得出解密方式。
但是如果我們使用非對稱加密就可以避免以上問題。
非對稱加密算法需要兩個密鑰來進(jìn)行加密和解密，這兩個秘鑰是公開密鑰（public key，簡稱公鑰）和私有密鑰（private key，簡稱私鑰）。
工作過程如下，甲乙之間使用非對稱加密的方式完成了重要信息的安全傳輸。
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乙方生成一對密鑰（公鑰和私鑰）并將公鑰向其它方公開。
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得到該公鑰的甲方使用該密鑰對機(jī)密信息進(jìn)行加密后再發(fā)送給乙方。
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乙方再用自己保存的另一把專用密鑰（私鑰）對加密后的信息進(jìn)行解密。乙方只能用其專用密鑰（私鑰）解密由對應(yīng)的公鑰加密后的信息。
在傳輸過程中，即使攻擊者截獲了傳輸?shù)拿芪?，并得到了乙的公鑰，也無法破解密文，因為只有乙的私鑰才能解密密文。
同樣，如果乙要回復(fù)加密信息給甲，那么需要甲先公布甲的公鑰給乙用于加密，甲自己保存甲的私鑰用于解密。
在非對稱加密中使用的主要算法有：RSA、Elgamal、背包算法、Rabin、D-H、ECC（橢圓曲線加密算法）等。
下面我們通過一個例子來說明如何用PHP來實現(xiàn)RSA的加密解密。
<?php class Rsa { public $privateKey = ''; public $publicKey = ''; public function __construct() {
$resource = openssl_pkey_new();
openssl_pkey_export($resource, $this->privateKey);
$detail = openssl_pkey_get_details($resource); $this->publicKey = $detail['key'];
} public function publicEncrypt($data, $publicKey) {
openssl_public_encrypt($data, $encrypted, $publicKey); return $encrypted;
} public function publicDecrypt($data, $publicKey) {
openssl_public_decrypt($data, $decrypted, $publicKey); return $decrypted;
} public function privateEncrypt($data, $privateKey) {
openssl_private_encrypt($data, $encrypted, $privateKey); return $encrypted;
} public function privateDecrypt($data, $privateKey) {
openssl_private_decrypt($data, $decrypted, $privateKey); return $decrypted;
}
}
$rsa = new Rsa(); echo "公鑰：\n", $rsa->publicKey, "\n"; echo "私鑰：\n", $rsa->privateKey, "\n"; $str = $rsa->publicEncrypt('hello', $rsa->publicKey); $str = base64_encode($str); echo "公鑰加密（base64處理過）：\n", $str, "\n";
$str = base64_decode($str);
$pubstr = $rsa->publicDecrypt($str, $rsa->publicKey); echo "公鑰解密：\n", $pubstr, "\n";
$privstr = $rsa->privateDecrypt($str, $rsa->privateKey); echo "私鑰解密：\n", $privstr, "\n"; $str = $rsa->privateEncrypt('world', $rsa->privateKey); $str = base64_encode($str); echo "私鑰加密（base64處理過）：\n", $str, "\n";
$str = base64_decode($str);
$pubstr = $rsa->publicDecrypt($str, $rsa->publicKey); echo "公鑰解密：\n", $pubstr, "\n";
$privstr = $rsa->privateDecrypt($str, $rsa->privateKey); echo "私鑰解密：\n", $privstr, "\n";
大家執(zhí)行一下可以看到公鑰加密的數(shù)據(jù)，只有私鑰能解密，反之亦然，私鑰加密的數(shù)據(jù)只有公鑰能解碼。
執(zhí)行結(jié)果如下：
這是PHP端的實現(xiàn)，可用在第三方跟平臺之間的數(shù)據(jù)傳輸，但如果是前端傳到后端該怎么辦呢，搜索了一下，發(fā)現(xiàn)了這個庫jsencrypt。
使用jsencrypt加密解密的例子如下：
<!DOCTYPE html> <html> <head> <title>JSEncrypt Example</title> <base id="basetag" href="/jsencrypt-2.3.0/"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <script src="jquery.js"></script> <script type="text/javascript" src="bin/jsencrypt.js"></script> </head> <body> <div class="container"> <script type="text/javascript"> $(function() { $('#testme').click(function() { var encrypt = new JSEncrypt();
encrypt.setPublicKey($('#pubkey').val()); var encrypted = encrypt.encrypt($('#input').val()); console.log(encrypted) var decrypt = new JSEncrypt();
decrypt.setPrivateKey($('#privkey').val()); var uncrypted = decrypt.decrypt(encrypted); console.log(uncrypted) if (uncrypted == $('#input').val()) {
alert('It works!!!');
} else {
alert('Something went wrong....');
}
});
}); </script> <label for="privkey">Private Key</label><br/> <textarea id="privkey" rows="15" cols="65">-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----</textarea><br/> <label for="pubkey">Public Key</label><br/> <textarea id="pubkey" rows="15" cols="65">-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA5GkymwBEbyRhNIxrHT11
CNRaTtbg5AZLrkFOC0b9ELsPa/I/n1TZDfa2VVzFezIhjoG/NGdJPc0cWeSljqjJ
0pa6cjt1o4RaQyXkpqmeMCzBcJsa699QI2mw+TZH/XUO0YhCLjOPYNu/jNzhb3SD
3C4Asl55JfBcAXHgbN/EGwl2OTK8JWa9d8lmZ8o+n22xvLeGrQMyem549xWbr8pw
t0JzGlYumJ0yJQTlDh7arf47FEzglpMCqpGYfkWRdn8dyBZEqSQDjIE+aY0p3xCZ
CuROCSR6Gy6P3RTtCexr3vqm/5XyfVKZ2Xu/DdUwL2yYjWaDdtoIW7iAFjOaqiKj
swIDAQAB
-----END PUBLIC KEY-----</textarea><br/> <label for="input">Text to encrypt:</label><br/> <textarea id="input" name="input" type="text" rows=4 cols=70>This is a test!</textarea><br/> <input id="testme" type="button" value="Test Me!!!" /><br/> </div> </body> </html>
其中的公鑰和私鑰都是上面PHP代碼中生成的，這邊好像只有公鑰加密，私鑰解密。
拿到其中打印出的加密后的數(shù)據(jù)，嘗試在PHP中進(jìn)行解密，可以看到也能解密成功。代碼如下：
<?php class Rsa { public $privateKey = '-----BEGIN PRIVATE KEY-----
MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQDkaTKbAERvJGE0
jGsdPXUI1FpO1uDkBkuuQU4LRv0Quw9r8j+fVNkN9rZVXMV7MiGOgb80Z0k9zRxZ
5KWOqMnSlrpyO3WjhFpDJeSmqZ4wLMFwmxrr31AjabD5Nkf9dQ7RiEIuM49g27+M
3OFvdIPcLgCyXnkl8FwBceBs38QbCXY5MrwlZr13yWZnyj6fbbG8t4atAzJ6bnj3
FZuvynC3QnMaVi6YnTIlBOUOHtqt/jsUTOCWkwKqkZh+RZF2fx3IFkSpJAOMgT5p
jSnfEJkK5E4JJHobLo/dFO0J7Gve+qb/lfJ9UpnZe78N1TAvbJiNZoN22ghbuIAW
M5qqIqOzAgMBAAECggEBAItUJFtqoVQOpADy+s/+UirNpjzbVJmjwXyNN3cnmW0g
PjsBrY+aqUCcUwLlMU2B+fg86w6jRokdWgL3t4m7Kkl8SkUuQgc5z/mP3tdPNkB6
vJDc/GIPeYnwidSrKOTSB/UGoiAesYJK6aCaiCV9tIWVxjUH7eyXnvf+qAChyrUW
PG/FirLyYmz1yRG99VKKE+iEIzemGSswU0DI0bwTFQ0MunLeJf0EdT20XppNwnl4
uoRgOBpMkW02vxDDWke2YIpk128KFRtPE3zF7W+Prb3ifMuQHSqDdqTgZA5+G3A9
D+lwczy95+0mIBpJ8rKQGjJ51ZT5WVMET9+Hb9+nUIECgYEA9NluRzIi9tZxwQa2
KdU8WAtWZZQZfG18mSFg8/QYrAGF2TyLAW0mEIe7nQXxPzm50HdpxTJCkUrXGm3u
hfPayx18H4oVVYRepSSfV+xe7wdogJWV6i5h/LaZsiTk1O8vF9Cwc3yUyVoMtKsg
yVcsONOzo/Kg/vwejQJb1C8dNvMCgYEA7tAewjA25vDmfiWZ0lrWKlwGQZ97+pMU
X+N12DWxL1Lvi6jBKXlK+Eiz19Qm/mBz9RxrDDY4/o0IjtTxdOh5thDaiqIcnqQn
PiBpm7zbheZOlPBGjFJ1vwueIWvqbx9vcqHik/4xHwuFNwQ+YCSpVpVoqrgoN/h/
fX5+hKm1kEECgYEAzn69UZAICtLKNveZE+jBLqPJJnvjjpur1F1hLfzz/cR/BLnZ
pcdOrew7Hu+PCTp+6kB7VJLRr0VF6gVCf3gsUta4AsVqvqeXRoF/XSB84+wEh0Ug
nNKnUwEQ2DvjPW3G8rfOyGcN+E5YntogGY3KPtbUDvWmL8WjYlrV5Toi0l8CgYAQ
Ujr37JGkAOzPzEQSA1FFvdpTm9G+U1T+JK6GI01DvbhPZC4nZnnAND/OTVqI4hCq
vNF4GTCV/Q+Lq3QBGG5RCh/Vf7TTBscD0PVGxoZ+RTozpaQ8rNoNP38EK7ru80gL
npK8qI+03nWxR+H3cin8l+N6X3GoOZyE+CMvb+XPwQKBgEeDjwTWxVhH/uksO3pw
MgbHjauD6AjuW9jc2a7ngFCWSQxQ3+xK1Spn6pbVdLPiBgInxCIl8d6S1yFU0Uan
iZHgy4fs1hdJRSuJ6qydqSwlS2C+gDpyY8ye0i+jq5VYYhKcpJCrCgaQGbleuaUd
ldp7v1FD8uyeemknGA35f6Id
-----END PRIVATE KEY-----'; public $publicKey = '-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA5GkymwBEbyRhNIxrHT11
CNRaTtbg5AZLrkFOC0b9ELsPa/I/n1TZDfa2VVzFezIhjoG/NGdJPc0cWeSljqjJ
0pa6cjt1o4RaQyXkpqmeMCzBcJsa699QI2mw+TZH/XUO0YhCLjOPYNu/jNzhb3SD
3C4Asl55JfBcAXHgbN/EGwl2OTK8JWa9d8lmZ8o+n22xvLeGrQMyem549xWbr8pw
t0JzGlYumJ0yJQTlDh7arf47FEzglpMCqpGYfkWRdn8dyBZEqSQDjIE+aY0p3xCZ
CuROCSR6Gy6P3RTtCexr3vqm/5XyfVKZ2Xu/DdUwL2yYjWaDdtoIW7iAFjOaqiKj
swIDAQAB
-----END PUBLIC KEY-----'; public function __construct() {
} public function publicEncrypt($data, $publicKey) {
openssl_public_encrypt($data, $encrypted, $publicKey); return $encrypted;
} public function publicDecrypt($data, $publicKey) {
openssl_public_decrypt($data, $decrypted, $publicKey); return $decrypted;
} public function privateEncrypt($data, $privateKey) {
openssl_private_encrypt($data, $encrypted, $privateKey); return $encrypted;
} public function privateDecrypt($data, $privateKey) {
openssl_private_decrypt($data, $decrypted, $privateKey); return $decrypted;
}
}
$rsa = new Rsa(); $str = 'IUMBGcLwJECdxUu3LMbeEhGQdoRjCLqFwfZQBO/Odh3tClbq76Tva7yYqTVxexXLmZ3uY8DrOk/XwcVVRr6g9rBnv/zxBxUShCdN0CwkoguvI+6Oju2aUBlM4FhUp+gmasa5YfqylEp1RpsVAp67GMGlxZvp0ekfhFXkjSqAguPd7dKq5YjftP12xOyuJHAzzg7U+eHxffxnneKqXkK7QrfQD6VrLpbYmayPSjMza/RbjXF+d85UeUZUaF25PZ7Y7kD4Yo7/hY/L6peeOkI5//tpl6U4QY9VsFsjAbIpNMsZuNjE/cZ57Kc5WScPsmy0o9wsp5DUEJmu+YYmr6adoA==';
$str = base64_decode($str);
$pubstr = $rsa->publicDecrypt($str, $rsa->publicKey); echo "公鑰解密：\n", $pubstr, "\n";
$privstr = $rsa->privateDecrypt($str, $rsa->privateKey); echo "私鑰解密：\n", $privstr, "\n";
解碼結(jié)果如下：
蕪湖市聰明屋智能科技有限公司（原中江網(wǎng)絡(luò)），成立于2005年，經(jīng)過10多年定制開發(fā)經(jīng)驗，積累了大量技術(shù)儲備和定制開發(fā)經(jīng)驗，率先創(chuàng)建安徽省內(nèi)自主研發(fā)的云計算平臺，具有大數(shù)據(jù)、高并發(fā)等高強(qiáng)度計算能力，為眾多政府、學(xué)校、公安部門、中小企業(yè)解決數(shù)據(jù)計算與管理難題。2013年公司內(nèi)部專門創(chuàng)建電商服務(wù)部，為企業(yè)提供全方位電商解決方案與配套服務(wù)。多次獲得國家、省市級領(lǐng)導(dǎo)接見，被國內(nèi)近20家電視臺、報紙媒體爭相報道。至今，聰明屋智能科技服務(wù)過上市公司、大型國企、各類私企超800家，為多家公司提供各類政務(wù)系統(tǒng)、app開發(fā)定制、微信小程序開發(fā)定制、智能家居、電商系統(tǒng)、連鎖收銀等技術(shù)解決方案服務(wù)。同時，聰明屋智能科技在智能硬件方面、區(qū)塊鏈應(yīng)用方面持續(xù)投入關(guān)注及創(chuàng)新。
