需要先了解的openssl系列函式

• openssl_pkey_get_private 從證書中解析獲取私鑰，以供使用。成功，返回真實的金鑰資源識別符號(Resource ID),否則返回false
• openssl_pkey_get_public 從證書中解析獲取公鑰，以供使用。成功，返回真實的金鑰資源識別符號(Resource ID),否則返回false
• openssl_private_encrypt($data, $encrypted, $privateKeyResourceID, OPENSSL_PKCS1_PADDING)
• //使用私鑰key加密資料data並且將結果儲存至變數crypted中
• openssl_public_decrypt(base64_decode($encrypted), $decrypted, $publicKeyResourceID, OPENSSL_PKCS1_PADDING)
• //私鑰加密的內容通過公鑰可用解密出來

<?php
/**
 * Created by PhpStorm.
 * User: zrj
 * Date: 18-11-7
 * Time: 上午10:22
 */
declare(strict_types=1);//開啟強型別模式

//私匙
$privateKeyString = <<<EOF
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
EOF;

//公匙
$publicKeyString = <<<EOF
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxHS1H/9uMS+waaP8vkEH
x0EJWqPnRjYIzHKrXeMQ3fjZmxPGMJmzwKVdADQlaFbA/NePu7dVFyzFo2yrAFlJ
D9bWs6of79OM2QGxu/AL2GqwjaOZ/+5tSkxqU8fj+/sb35U9kGxy/k4KPwlatTaH
IkXb7qebCGX1hgNw2BkRrNfXWRX+EVs8Oy/I/d1CMQMF3mvsCFvoUAE/UJVOOAjj
Q6rBX+PorWXuTIKgWgSFWwzsRWJNhQo6P6Y/amx2Jb6Nr0rHIJIREICdYMAp2DSC
+uU+jl85NqT3U89BRRG+58feoUOLDGiv0hRQ7+k1e47MfiwKpCpJOkldEJjywMhl
1QIDAQAB
-----END PUBLIC KEY-----
EOF;

$data = "helloworld";

try {
    //從證書中解析獲取私鑰。成功，返回真實的金鑰資源識別符號
    $privateKeyResourceID = openssl_pkey_get_private($privateKeyString);
    if ($privateKeyResourceID === false) throw new \Exception('private key string is wrong');

    //從證書中解析獲取公鑰，以供使用。成功，返回真實的金鑰資源識別符號
    $publicKeyResourceID = openssl_pkey_get_public($publicKeyString);//這個函式可用來判斷公鑰是否是可用的
    if ($publicKeyResourceID === false) throw new \Exception('public key string is wrong');

    //使用私鑰key加密資料data並且將結果儲存至變數crypted中。
    //加密後的資料可以通過openssl_public_decrypt()函式來解密。
    openssl_private_encrypt($data, $encrypted, $privateKeyResourceID, OPENSSL_PKCS1_PADDING);

    //私鑰加密
    $encrypted = base64_encode($encrypted);//加密之後的結果,base64只是為了避免特殊字元

    openssl_public_decrypt(base64_decode($encrypted), $decrypted, $publicKeyResourceID, OPENSSL_PKCS1_PADDING);//私鑰加密的內容通過公鑰可用解密出來

    echo $decrypted . PHP_EOL;

} catch (\Exception $e) {
    die($e->getMessage());
}