Each time this page is opened, the backend generates a certificate based on Session

if(!isset($_SESSION['key_pub'])){
            $rsa_model=new \Home\Library\Org\Util\Rsa();
            $_SESSION['key_pub']=$rsa_model->privateKey;
            $_SESSION['key_pri']=$rsa_model->privateKey;
 }
$this->assign("pub_token",$_SESSION['key_pub']);
$this->display('index');

This is used to log off session s

public function logout(){
        session(null);
    }

Verify that the certificate is available

public function check(){
        $codekey=I("post.codekey");
        if($codekey!=null){
            if(isset($_SESSION['key_pri'])){
                $rsa=new \Home\Library\Org\Util\Rsa();
                $rsa->privateKey=$_SESSION['key_pri'];
                $rsa->publicKey=$_SESSION['key_pub'];
                $privstr = $rsa->privateDecrypt(base64_decode($codekey),$rsa->privateKey);
                //Delete the original key pair after decryption is complete and wait for reassignment
                $_SESSION['key_pub']=null;
                $_SESSION['key_pri']=null;
                echo $privstr;
            }
        }
    }

Well, code like this, consider scenarios
There is Server A, Client B
Each access to the server produces a session that generates and stores a pair of rsa keys within the valid time of the session. The public key is assigned to B by the server backend. B verifies that A is valid by verifying A's international certificate.When sending data to A, the data from B is encrypted and signed by the public key just assigned by A. A decrypts the data from B by the public and private keys. A successful decryption indicates that the valid validation of B data is successful.

Assign A public key to B as shown in the diagram request

The left column of B is the data to reply to A, and the right column is the data after A has been signed by the public key
After clicking Test, you can see that data signed with the public key and encoded as base64 is sent to the back end

A decrypts the message from B and replies to B

The plaintext after decryption is identical to the plaintext local to B, and the verification is successful.
Front-end encrypted code is attached below

$(function() {
        $('#testme').click(function() {

            var encrypt = new JSEncrypt();
            encrypt.setPublicKey($('#pub_key').attr("content"));
            var encrypted = encrypt.encrypt($('#text').val());
            $('#output').val(encrypted);

            $.ajax({
                type:"POST",
                url:"http://127.0.0.1/index.php/home/index/check",
                data:{codekey:$('#output').val()},
                dataType:"html",
                success:function (data) {
                    alert(data);
                }

            });
        });
    });

Reference Library Files

<script src="http://code.jquery.com/jquery-1.8.3.min.js"></script>
<script src="__PUBLIC__/js/jsencrypt.min.js"></script>