PHP的学习--RSA加密解密

PHP服务端与客户端交互或者提供开放API时，通常需要对敏感的数据进行加密，这时候rsa非对称加密就能派上用处了。

举个通俗易懂的例子，假设我们再登录一个网站，发送账号和密码，请求被拦截了。

密码没加密，那攻击者就直接拿到了密码，这是最搓的。
密码加密了，是不可逆加密，那攻击者只需要模拟那个请求即可登录。
密码加密了，是可逆加密，其中携带有时间等参数，后台可以根据时间等参数来判断是否有效，但因为是在前端加密，其加密方式也能在代码中找到，找到加密方式就可以得出解密方式。

但是如果我们使用非对称加密就可以避免以上问题。

非对称加密算法需要两个密钥来进行加密和解密，这两个秘钥是公开密钥（public key，简称公钥）和私有密钥（private key，简称私钥）。

工作过程如下，甲乙之间使用非对称加密的方式完成了重要信息的安全传输。

非对称加密工作过程简要示意图

乙方生成一对密钥（公钥和私钥）并将公钥向其它方公开。
得到该公钥的甲方使用该密钥对机密信息进行加密后再发送给乙方。
乙方再用自己保存的另一把专用密钥（私钥）对加密后的信息进行解密。乙方只能用其专用密钥（私钥）解密由对应的公钥加密后的信息。

在传输过程中，即使攻击者截获了传输的密文，并得到了乙的公钥，也无法破解密文，因为只有乙的私钥才能解密密文。
同样，如果乙要回复加密信息给甲，那么需要甲先公布甲的公钥给乙用于加密，甲自己保存甲的私钥用于解密。

在非对称加密中使用的主要算法有：RSA、Elgamal、背包算法、Rabin、D-H、ECC（椭圆曲线加密算法）等。

下面我们通过一个例子来说明如何用PHP来实现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 "公钥：\n", $rsa->publicKey, "\n";
echo "私钥：\n", $rsa->privateKey, "\n";// 使用公钥加密
$str = $rsa->publicEncrypt('hello', $rsa->publicKey);
// 这里使用base64是为了不出现乱码，默认加密出来的值有乱码
$str = base64_encode($str);
echo "公钥加密（base64处理过）：\n", $str, "\n";
$str = base64_decode($str);
$pubstr = $rsa->publicDecrypt($str, $rsa->publicKey);
echo "公钥解密：\n", $pubstr, "\n";
$privstr = $rsa->privateDecrypt($str, $rsa->privateKey);
echo "私钥解密：\n", $privstr, "\n";// 使用私钥加密
$str = $rsa->privateEncrypt('world', $rsa->privateKey);
// 这里使用base64是为了不出现乱码，默认加密出来的值有乱码
$str = base64_encode($str);
echo "私钥加密（base64处理过）：\n", $str, "\n";
$str = base64_decode($str);
$pubstr = $rsa->publicDecrypt($str, $rsa->publicKey);
echo "公钥解密：\n", $pubstr, "\n";
$privstr = $rsa->privateDecrypt($str, $rsa->privateKey);
echo "私钥解密：\n", $privstr, "\n";

大家执行一下可以看到公钥加密的数据，只有私钥能解密，反之亦然，私钥加密的数据只有公钥能解码。

执行结果如下：

这是PHP端的实现，可用在第三方跟平台之间的数据传输，但如果是前端传到后端该怎么办呢，搜索了一下，发现了这个库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">// Call this code when the page is done loading.$(function() {// Run a quick encryption/decryption when they click.$('#testme').click(function() {// Encrypt with the public key...var encrypt = new JSEncrypt();encrypt.setPublicKey($('#pubkey').val());var encrypted = encrypt.encrypt($('#input').val());console.log(encrypted)// Decrypt with the private key...var decrypt = new JSEncrypt();decrypt.setPrivateKey($('#privkey').val());var uncrypted = decrypt.decrypt(encrypted);console.log(uncrypted)// Now a simple check to see if the round-trip worked.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-----
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-----</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>

其中的公钥和私钥都是上面PHP代码中生成的，这边好像只有公钥加密，私钥解密。

拿到其中打印出的加密后的数据，尝试在PHP中进行解密，可以看到也能解密成功。代码如下：

<?php
class Rsa
{public $privateKey = '-----BEGIN PRIVATE KEY-----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-----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();// 使用公钥加密的内容
$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 "公钥解密：\n", $pubstr, "\n";
$privstr = $rsa->privateDecrypt($str, $rsa->privateKey);
echo "私钥解密：\n", $privstr, "\n";

解码结果如下：