openssl genrsa -out rsa_private_key.pem 1024
openssl pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt -out private_key.pem
openssl rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem

$fp=fopen("rsa/rsa_private_key.pem","r"); //你的私钥文件路径
$private_key=fread($fp,8192);
fclose($fp);
$fp1=fopen("rsa/rsa_public_key.pem","r"); //你的公钥文件路径
$public_key=fread($fp1,8192);
fclose($fp1);
//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($pi_key);echo "\n"; echo "<br>";
print_r($pu_key);echo "\n"; echo "<br>";
echo "<hr>";
$data='php ras加密算法';
$encrypted = ""; 
$decrypted = ""; 
echo "加密的源数据:".$data."\n"; echo "<br>";
echo "private key encrypt:\n"; echo "<br>";
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 '私钥加密后：'.$encrypted."\n"; echo "<br>";echo "<br>";
echo "public key decrypt:\n"; echo "<br>";
openssl_public_decrypt(base64_decode($encrypted),$decrypted,$pu_key);//私钥加密的内容通过公钥可用解密出来 
echo '公钥解密后：'.$decrypted."\n"; echo "<br>";
echo "<hr>";
echo "public key encrypt:\n"; echo "<br>";
openssl_public_encrypt($data,$encrypted,$pu_key);//公钥加密 
$encrypted = base64_encode($encrypted); 
echo $encrypted,"\n"; echo "<br>";
echo "private key decrypt:\n"; echo "<br>";
openssl_private_decrypt(base64_decode($encrypted),$decrypted,$pi_key);//私钥解密 
echo $decrypted,"\n"; echo "<br>";