Use RSA between android and go

I fix it !

I generate public and private key with this Go code :

/*
 * Genarate rsa keys.
*/

package main

import (
    "crypto/rand"
    "crypto/rsa"
    "crypto/x509"
    "encoding/gob"
    "encoding/pem"
    "fmt"
    "os"
)

func main() {
    reader := rand.Reader
    bitSize := 2048

    key, err := rsa.GenerateKey(reader, bitSize)
    checkError(err)

    publicKey := key.PublicKey

    saveGobKey("private.key", key)
    savePEMKey("private.pem", key)

    saveGobKey("public.key", publicKey)
    savePublicPEMKey("public.pem", publicKey)
}

func saveGobKey(fileName string, key interface{}) {
    outFile, err := os.Create(fileName)
    checkError(err)
    defer outFile.Close()

    encoder := gob.NewEncoder(outFile)
    err = encoder.Encode(key)
    checkError(err)
}

func savePEMKey(fileName string, key *rsa.PrivateKey) {
    outFile, err := os.Create(fileName)
    checkError(err)
    defer outFile.Close()

    var privateKey = &pem.Block{
        Type:  "PRIVATE KEY",
        Bytes: x509.MarshalPKCS1PrivateKey(key),
    }

    err = pem.Encode(outFile, privateKey)
    checkError(err)
}

func savePublicPEMKey(fileName string, pubkey rsa.PublicKey) {
    asn1Bytes, err := x509.MarshalPKIXPublicKey(&pubkey)
    checkError(err)

    var pemkey = &pem.Block{
        Type:  "PUBLIC KEY",
        Bytes: asn1Bytes,
    }

    pemfile, err := os.Create(fileName)
    checkError(err)
    defer pemfile.Close()

    err = pem.Encode(pemfile, pemkey)
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        fmt.Println("Fatal error ", err.Error())
        os.Exit(1)
    }
}

and then i encrypt my message in android with generated public key in GO:

static PublicKey serveruk;


public final static String chi="RSA/ECB/OAEPPadding";

public final static String RSA = "RSA";

private final static int CRYPTO_BITS = 512;


String pubPEM = "public key from public.pem";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    stringToPublicKeytoserver(pubPEM);
    Log.e("ENCODED", enc4golang("Please hide me !"));

}


public static PublicKey stringToPublicKeytoserver(String publicKeyString)
{
    try {
        publicKeyString = publicKeyString.replace("-----BEGIN PUBLIC KEY-----", "");
        publicKeyString = publicKeyString.replace("-----END PUBLIC KEY-----", "");
        byte[] keyBytes = Base64.decode(publicKeyString, Base64.DEFAULT);
        X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(RSA);
        serveruk=keyFactory.generatePublic(spec);
        return serveruk;
    } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
        e.printStackTrace();
        return null;
    }
}


private static byte[] enc4golang(String text, PublicKey pubRSA) throws Exception{
    Cipher cipher = Cipher.getInstance(chi);
    cipher.init(Cipher.ENCRYPT_MODE, pubRSA);
    return cipher.doFinal(text.getBytes("UTF-8")); //i also advice you to use: .getBytes("UTF-8"); instead of data.getBytes();
}


public final static String enc4golang(String text){
    try {
        return Base64.encodeToString(enc4golang(text, serveruk) ,Base64.DEFAULT);  //send this string to golang
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }
    return null;
}

and then i decrypt it with this GO code:

package main

import (
    "crypto/rand"
    "crypto/rsa"
    "crypto/sha1"
    "crypto/x509"
    "encoding/base64"
    "encoding/pem"
)

func main(){

    const priPEM = `private key from private.pem`

    const pubPEM = `public key from public.pem`

    base64DecodeBytes, err := base64.StdEncoding.DecodeString("encrypted data from android")
    if err != nil {
        panic(err)
    }
    privateKeyBlock, _ := pem.Decode([]byte(priPEM))
    var pri *rsa.PrivateKey
    pri, parseErr := x509.ParsePKCS1PrivateKey(privateKeyBlock.Bytes)
    if parseErr != nil {
        panic(parseErr)
    }
    decryptedData, decryptErr := rsa.DecryptOAEP(sha1.New(), rand.Reader, pri, base64DecodeBytes, nil)
    if decryptErr != nil {
        panic(decryptErr)
    }

    print(string(decryptedData))

}