👀 Views: 89 💬 Answers: 1 📅 Created: 2025-09-17

iOS security URLSession SSL certificate-pinning swift

I'm a bit lost with I've been struggling with this for a few days now and could really use some help. I'm not sure how to approach Recently started working on a project that requires implementing a secure communication channel for sensitive data transmission in iOS... My goal is to ensure that all transmitted data is encrypted and that the app is protected against man-in-the-middle attacks. To achieve this, I decided to implement SSL pinning using `URLSession`. Initially, I set up a simple `URLSession` as follows: ```swift let session = URLSession(configuration: .default) let url = URL(string: "https://api.example.com/data")! let task = session.dataTask(with: url) { data, response, error in if let error = error { print("Error: \(error)") return } // Process data here } task.resume() ``` While testing, I found that the data was being transmitted securely, but I wanted an extra layer of protection. I then researched and started implementing certificate pinning. Following a guide, I attempted to override `URLSessionDelegate` as shown below: ```swift class CustomSessionDelegate: NSObject, URLSessionDelegate { func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) { if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust { if let serverTrust = challenge.protectionSpace.serverTrust { // Load the local certificate and compare // Assuming you have a function to load the certificate let localCertificate = loadLocalCertificate() let isCertificateValid = validateCertificate(serverTrust: serverTrust, localCertificate: localCertificate) if isCertificateValid { let credential = URLCredential(trust: serverTrust) completionHandler(.useCredential, credential) return } } } completionHandler(.performDefaultHandling, nil) } } ``` Unfortunately, despite implementing this, the app crashes when it attempts to validate the server certificate. The error message states: "The certificate is invalid." I suspect that the issue may be related to how I'm loading the local certificate or possibly an issue with trusting the certificate chain. I've double-checked the local certificate and ensured it matches the server's certificate. Additionally, I have verified that the certificate is included in the app bundle. Still, I’m unsure how to troubleshoot the validation logic further. Does anyone have insights on best practices for implementing SSL pinning in iOS, or can you suggest debugging strategies for certificate validation? Any assistance in this matter would be greatly appreciated. Is there a better approach? I recently upgraded to Swift 3.10. Any pointers in the right direction? I'm coming from a different tech stack and learning Swift. I'd love to hear your thoughts on this. Is there a simpler solution I'm overlooking?