---
title: NSURLProtectionSpace authentication method constants
framework: foundation
role: collectionGroup
role_heading: API Collection
path: foundation/nsurlprotectionspace-authentication-method-constants
---

# NSURLProtectionSpace authentication method constants

Constants describing known values of the authenticationMethod property of a URLProtectionSpace.

## Overview

Overview These constants are also used with the URLProtectionSpace initializers init(host:port:protocol:realm:authenticationMethod:) and init(proxyHost:port:type:realm:authenticationMethod:).

## Topics

### Session-wide authentication challenges

- [NSURLAuthenticationMethodClientCertificate](foundation/nsurlauthenticationmethodclientcertificate.md)
- [NSURLAuthenticationMethodNegotiate](foundation/nsurlauthenticationmethodnegotiate.md)
- [NSURLAuthenticationMethodNTLM](foundation/nsurlauthenticationmethodntlm.md)
- [NSURLAuthenticationMethodServerTrust](foundation/nsurlauthenticationmethodservertrust.md)

### Task-specific authentication challenges

- [NSURLAuthenticationMethodDefault](foundation/nsurlauthenticationmethoddefault.md)
- [NSURLAuthenticationMethodHTMLForm](foundation/nsurlauthenticationmethodhtmlform.md)
- [NSURLAuthenticationMethodHTTPBasic](foundation/nsurlauthenticationmethodhttpbasic.md)
- [NSURLAuthenticationMethodHTTPDigest](foundation/nsurlauthenticationmethodhttpdigest.md)

## See Also

### Related Documentation

- [Handling an authentication challenge](foundation/handling-an-authentication-challenge.md)
- [Performing manual server trust authentication](foundation/performing-manual-server-trust-authentication.md)

### Identifying protection space properties

- [NSURLProtectionSpace protocol types](foundation/nsurlprotectionspace-protocol-types.md)
- [NSURLProtectionSpace proxy types](foundation/nsurlprotectionspace-proxy-types.md)