Implementation of SSL pinning (using certifcate)

CertificatePinning.swift

func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        guard let serverTrust = challenge.protectionSpace.serverTrust else {
            completionHandler(.cancelAuthenticationChallenge, nil);
            return
        }
        
        let certificate = SecTrustGetCertificateAtIndex(serverTrust, 0)
        
        // SSL Policies for domain name check
        let policy = NSMutableArray()
        policy.add(SecPolicyCreateSSL(true, challenge.protectionSpace.host as CFString))
        
        //evaluate server certifiacte
        let isServerTrusted = SecTrustEvaluateWithError(serverTrust, nil)
        
        //Local and Remote certificate Data
        let remoteCertificateData:NSData =  SecCertificateCopyData(certificate!)
        
        let pathToCertificate = Bundle.main.path(forResource: "mocky", ofType: "cer")
        let localCertificateData:NSData = NSData(contentsOfFile: pathToCertificate!)!
        //Compare certificates
        if(isServerTrusted && remoteCertificateData.isEqual(to: localCertificateData as Data)){
            let credential:URLCredential =  URLCredential(trust:serverTrust)
            print("Certificate pinning is successfully completed")
            completionHandler(.useCredential,nil)
        }
        else {
            DispatchQueue.main.async {
                self.showAlert(text: "SSL Pinning", message: "Pinning failed")
            }
            completionHandler(.cancelAuthenticationChallenge,nil)
        }
    }