Renci.SshNet.ClientAuthentication.TryAuthenticate C# (CSharp) Method

        private static bool TryAuthenticate(ISession session,
                                            AuthenticationState authenticationState,
                                            ICollection<string> allowedAuthenticationMethods,
                                            ref SshAuthenticationException authenticationException)
        {
            if (allowedAuthenticationMethods.Count == 0)
            {
                authenticationException = new SshAuthenticationException("No authentication methods defined on SSH server.");
                return false;
            }

            // we want to try authentication methods in the order in which they were
            // passed in the ctor, not the order in which the SSH server returns
            // the allowed authentication methods
            var matchingAuthenticationMethods = authenticationState.SupportedAuthenticationMethods.Where(a => allowedAuthenticationMethods.Contains(a.Name)).ToList();
            if (matchingAuthenticationMethods.Count == 0)
            {
                authenticationException = new SshAuthenticationException(string.Format("No suitable authentication method found to complete authentication ({0}).", string.Join(",", allowedAuthenticationMethods.ToArray())));
                return false;
            }

            foreach (var authenticationMethod in GetOrderedAuthenticationMethods(authenticationState, matchingAuthenticationMethods))
            {
                if (authenticationState.FailedAuthenticationMethods.Contains(authenticationMethod))
                    continue;

                // when the authentication method was previously executed, then skip the authentication
                // method as long as there's another authentication method to try; this is done to avoid
                // a stack overflow for servers that do not update the list of allowed authentication
                // methods after a partial success

                if (!authenticationState.ExecutedAuthenticationMethods.Contains(authenticationMethod))
                {
                    // update state to reflect previosuly executed authentication methods
                    authenticationState.ExecutedAuthenticationMethods.Add(authenticationMethod);
                }

                var authenticationResult = authenticationMethod.Authenticate(session);
                switch (authenticationResult)
                {
                    case AuthenticationResult.PartialSuccess:
                        if (TryAuthenticate(session, authenticationState, authenticationMethod.AllowedAuthentications, ref authenticationException))
                        {
                            authenticationResult = AuthenticationResult.Success;
                        }
                        break;
                    case AuthenticationResult.Failure:
                        authenticationState.FailedAuthenticationMethods.Add(authenticationMethod);
                        authenticationException = new SshAuthenticationException(string.Format("Permission denied ({0}).", authenticationMethod.Name));
                        break;
                    case AuthenticationResult.Success:
                        authenticationException = null;
                        break;
                }

                if (authenticationResult == AuthenticationResult.Success)
                    return true;
            }

            return false;
        }