求Md5withRsa php 、python、或者nodejs的实现，或者给讲讲原理？

Question

客户接口是使用的java实现，验证使用的md5withrsa,拆开看都理解，放到一块就懵逼了，求讲解！！！！
附java的实现方式：

package main;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.security.SecureRandom;


public class main {
    
    /**
     * 生成秘钥
     */
    public static void makeKey()
    {
        String KEY_ALGORITHM = "rsa";
        java.security.KeyPairGenerator keygen;
        try {
            keygen = java.security.KeyPairGenerator
                    .getInstance(KEY_ALGORITHM );
            SecureRandom secrand = new SecureRandom();
            secrand.setSeed("tmriPayment".getBytes()); // 初始化随机产生器
            keygen.initialize(1024);
            KeyPair keys = keygen.genKeyPair();
            RSAPublicKey pubkey = (RSAPublicKey) keys.getPublic();
            RSAPrivateKey prikey = (RSAPrivateKey) keys.getPrivate();
            String pubKeyStr=  Base64Util.encodeBase64(pubkey.getEncoded());//得到公钥 并做base64编码
            String priKeyStr=  Base64Util.encodeBase64(prikey.getEncoded());//得到私钥 并做base64编码
            
            System.out.println("公钥:"+ pubKeyStr);
            System.out.println("私钥:"+ priKeyStr);
            
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    /**
     * 加密
     * @return
     */
    public static String encodeData()
    {
        
        try {
            
            byte[] data = "fdfdfsdfdfd".getBytes();
            String privateKey = "MIICXAIBAAKBgQDOF3dzQpPVIvHrx2qwszcv9Cw5XhCEyuRTy+HDPD684NSGGGnL"+
                    "34cLc1BCEjlT3v9H81SigvSUDB++YbMcZOrRFT+MAt22yi98BcRP60vgVixfTCCI"+
                    "lc39b6G6I6ac5BUfOKwdUKNUnCLvcojshmtGezcEYGocMziOIwXIdBXErQIDAQAB"+
                    "AoGANlycRovuQM9J7v6YFun/Cagnri4wv0ZhefUSpRQUHHBVvtVbuspIbe3J4tO5"+
                    "yXTN86Ws0n0mlJKqIObWfwvjoDADNeEWFXUI5YKyEnpnvvZwTo1JjrDy8QJpGe94"+
                    "yNebfGLKyZtIc/zLq9sFboyqNCtn2hu7IsG2g4SGe9BFcsUCQQDnrc6yXG6jmFC/"+
                    "7HFqXj5NtQc72vYbIjf32yG8W1D1j3ghZZwtUkIa8g3WMxFrYW9DFMzTDi3/mPSd"+
                    "1A9OG89DAkEA47oFZj6xf7gzDbHDdKX/S9ehjQjP2q6V7SYXnhdEwioxjJpj9qrP"+
                    "SKQg8A9m4nUl2FXJ2spxApotHoKHqTGFTwJBAIkcohGJBqmnQVL0mgK7l9/hXVCd"+
                    "O72/OKRlecfBu1449H2/ZvijkB/mVS4Jtyt31KM8siPOZoa4fTzS/ePaLYUCQDHj"+
                    "LY2hjFbzblPArpXeS5g8y8pOtOIuPu/t2Vyrskdq4OHxbJa8Ap7iPcj5RsuzaDAF"+
                    "UywYDzvHtLyrUbbR/2cCQGbbIWDLPtzHzI7QumtabHq9M5zUgvtXDksnOltcEDSX"+
                    "aBoGSbpRcPcGFfFMY+fd/kdmEambYn+270DNHPvqljU=";
            byte[] keyBytes;
            keyBytes = Base64Util.decodeBase64(privateKey);
            PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
            Signature signature = Signature.getInstance("MD5withRSA");
            signature.initSign(priKey);
            signature.update(data);//data为要生成签名的源数据字节数组
            return Base64Util.encodeBase64(Base64Util.encodeBase64(signature.sign()).getBytes());
            
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }//对私钥做base64解码
        

        return "";
    }
    
    
    /**
     * 解密
     * @return
     */
    public static Boolean decodeData(String msg)
    {
        String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDMrfAeCg5zyHJKs269vMywoMYwKWGfBbk31K44g0ZLg8YN4c9jOH4hyAYkhN5mWY69Q8Sb82OAlxBXMY1zQshKk6kzZGOrYDQOt/bvVg6kPdf9IgtWky4YaCVSR2C0zYCviz+pHXJrbTeyVVLmbaxsr2lEjamBoDcfM1uE9hj83QIDAQAB";
        
        try {
        byte[] data = "fdfdfsdfdfd".getBytes();
        byte[] publicKey1 = Base64Util.decodeBase64(publicKey);//对提供的公钥做base64解码
        
        byte[] sign = Base64Util.decodeBase64( new String(Base64Util.decodeBase64(msg)));//签名需要做二次base64解码
        
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey1);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey pubKey = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance("MD5withRSA");
        signature.initVerify(pubKey);
        signature.update(data);
        return signature.verify(sign);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }//对私钥做base64解码
        
        return false;

    }
    
    

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub

        //makeKey();
        
        String msg = encodeData();
        //System.out.println(msg);
        
        //String msg = "ZlBGVnVXQm1YVjhhWDhGbVVYV24raEJzRVB1WFAycUhKdVIwbGl3azY5T2VKWHBkMDlpL1U5aGYwcEVvK1h0M0RNMFNsRTNQM1pYazFyT25xblZwTStRZmJhVGVPUXBsZ0ozZVFKemFnaWt5dzNvUXRNZC81RGQ4RGlSR3pqUmRhOFd2OCt1ekRiakZBdWtqeGg3Y1plTEdTT2ppQ08rcFVqOUQxZXh6ZG1VPQ==";
        //Boolean data = decodeData(msg);
        //System.out.println(data);
    
    }

}