RSA 256 jwt verify method throws JsonWebTokenError: invalid signature - node.js

Question

I'm working on server to server authentication and I want to access one request from serverB.
So that I have created 2 RSA key file in serverA repo.
1.safety-private.key
2.safety-public.key
And I'm sending request to serverB by following code.
ServerA :
import { Injectable } from '#nestjs/common';
const jwt = require("jsonwebtoken");
const fs = require("fs");
#Injectable()
export class RsaTokenAuthService {
loadKey(path) {
if (!path) {
return null;
}
try {
return fs.readFileSync(path, { encoding: 'utf8' });
} catch (err) {
console.error(err);
}
}
exportRSAKey() {
return this.loadKey(process.env.JWT_RSA_PRIVATE_KEY);
}
getSigningConfig(subject) {
const rsaSignOptions = {
algorithm: 'RS256',
expiresIn: 15 * 60, // expires in 15min
issuer: process.env.ISSUER,
audience: `${process.env.FORM_API_URL}`,
};
if (this.exportRSAKey()) {
return {
options: { ...rsaSignOptions, subject },
secret: this.exportRSAKey(),
};
}
}
buildToken(subject, payload = {}) {
const sign = this.getSigningConfig(subject);
return jwt.sign(payload, sign.secret, sign.options);
}
}
ServerB:
Again I have created two RSA files in serverB repo
serverB-private.key
serverB-public.key
When I run both the server on localhost and having different port and try to verify the token it throws the invalid token error.
Here is my verification code on serverB.
const fs = require('fs')
const jwt = require("jsonwebtoken");
const rsaVerifyOptions = {
// only allow RSA + SHA256
algorithms: ["RS256"],
}
function loadKey(path) {
if (!path) {
return null;
}
try {
return fs.readFileSync(path, { encoding: 'utf8' });
} catch (err) {
console.error(err);
}
}
function exportRSAKey() {
return loadKey(process.env.JWT_RSA_PUBLIC_KEY);
}
function getVerifyConfig(subject) {
if (exportRSAKey()) {
return {
options: rsaVerifyOptions,
secret: exportRSAKey(),
};
}
}
function verifyToken(token) {
const { options, secret } = getVerifyConfig();
try {
return jwt.verify(token, secret, options);
} catch (err) {
// in prod, don't use console.log because it is synchronous
console.log(err);
return null;
}
}
function decodeAndVerify(req, res, next) {
// Authorization: Bearer <jwt-token>
// 1. extract Authrorization header
const authorizationHeader = req.get("Authorization");
if (!authorizationHeader) {
return res.status(401).json("missing token");
}
// 2. extract the JWT
// "Bearer: my-jwt-token"
const token = authorizationHeader.substring(7);
// 3. decode token
const decodedToken = verifyToken(token);
if (!decodedToken) {
return res.status(401).json("invalid token");
}
req.token = decodedToken;
next();
}
module.exports = {
verifyToken,
decodeAndVerify
}
Please help me. Am I doing wrong somewhere ? Thanks in advance :)