php - Go - How to Set RSA PublicKey Modulus from String? -

i trying encrypt password go's rsa package.

here have far:

package main  import (     "fmt"     "time"     "net/http"     "strconv"     "io/ioutil"     "encoding/json"     "errors"     "crypto/rsa"     "crypto/rand"     //"math/big" )  func main() {     if err := login("username", "password"); err != nil {         fmt.println(err)     } }  func login(username, password string) error {     donotcache := strconv.formatint(time.now().unixnano() / int64(time.millisecond), 10)      // rsa key     resp, err := http.postform("https://steamcommunity.com/login/getrsakey/", map[string][]string{         "donotcache": {donotcache},         "username": {username},     })     if err != nil {         return err     }      content, err := ioutil.readall(resp.body)     if err != nil {         return err     }      var decoded map[string]interface{}     err = json.unmarshal(content, &decoded)     if err != nil {         return err     }      if decoded["success"] != true {         return errors.new("failed retrieve rsa key.")     }      // set encryption variables     var privatekey *rsa.privatekey     var publickey *rsa.publickey     var plain_text, encrypted []byte      plain_text = []byte(password)      // generate private key     if privatekey, err = rsa.generatekey(rand.reader, 1024); err != nil {         return err     }      privatekey.precompute()      if err = privatekey.validate(); err != nil {         return err     }      publickey.n = decoded["publickey_mod"].(string) // <- not right, need create modulus publickey_mod string , needs of type big.int     publickey.e = decoded["publickey_exp"].(int)      encrypted, err = rsa.encryptpkcs1v15(rand.reader, publickey, plain_text)     if err != nil {         return err     }      fmt.printf("pkcs1 encrypted [%s] \n[%x]\n", string(plain_text), encrypted)      return nil } 

i unable set publickey.n value big.int given string.

variable decoded["publickey_mod"] looks this:

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

and variable decoded["publickey_mod"] looks 010001

i trying encrypt password https://steamcommunity.com/.

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i have encrypted exact method using php before class called math_biginteger , how made publickey , encrypted password:

$key = array(     'n' => new math_biginteger($curl->response->publickey_mod,16),     'e' => new math_biginteger($curl->response->publickey_exp,16) );  // define exponent define('crypt_rsa_exponent', 010001);  // load key $rsa->loadkey($key)  // set settings $rsa->setencryptionmode(crypt_rsa_encryption_pkcs1); $rsa->sethash('sha256');  // encrypt password $encrypted_password = base64_encode($rsa->encrypt($password)); 

help extremely appreciated, in advance.

https://play.golang.org/p/wmkgu2_q20

decoded["publickey_mod"] hex string, need convert big.int:

publickey.n, _ = new(big.int).setstring(decoded["publickey_mod"].(string), 16 /* = base 16 */) // json numbers float64 default unless use struct , force type publickey.e = int(decoded["publickey_exp"].(float64))