PHPでのrsa暗号化と復号化の詳細な説明

<?php
$private_key = &#39;-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----&#39;;

$public_key = &#39;-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC3//sR2tXw0wrC2DySx8vNGlqt
3Y7ldU9+LBLI6e1KS5lfc5jlTGF7KBTSkCHBM3ouEHWqp1ZJ85iJe59aF5gIB2kl
Bd6h4wrbbHA2XE1sq21ykja/Gqx7/IRia3zQfxGv/qEkyGOx+XALVoOlZqDwh76o
2n1vP1D+tD3amHsK7QIDAQAB
-----END PUBLIC KEY-----&#39;;

//echo $private_key;
$pi_key =  openssl_pkey_get_private($private_key);//这个函数可用来判断私钥是否是可用的，可用返回资源id Resource id
$pu_key = openssl_pkey_get_public($public_key);//这个函数可用来判断公钥是否是可用的
print_r($pi_key);echo "\n";
print_r($pu_key);echo "\n";


$data = "aassssasssddd";//原始数据
$encrypted = ""; 
$decrypted = ""; 

echo "source data:",$data,"\n";

echo "private key encrypt:\n";

openssl_private_encrypt($data,$encrypted,$pi_key);//私钥加密
$encrypted = base64_encode($encrypted);//加密后的内容通常含有特殊字符，需要编码转换下，在网络间通过url传输时要注意base64编码是否是url安全的
echo $encrypted,"\n";

echo "public key decrypt:\n";

openssl_public_decrypt(base64_decode($encrypted),$decrypted,$pu_key);//私钥加密的内容通过公钥可用解密出来
echo $decrypted,"\n";

echo "---------------------------------------\n";
echo "public key encrypt:\n";

openssl_public_encrypt($data,$encrypted,$pu_key);//公钥加密
$encrypted = base64_encode($encrypted);
echo $encrypted,"\n";

echo "private key decrypt:\n";
openssl_private_decrypt(base64_decode($encrypted),$decrypted,$pi_key);//私钥解密
echo $decrypted,"\n";