The HOTPin iOS Client (client software) is a component of the Celestix HOTPin 2-Factor Authentication System. The system provides a secure way for organizations to allow users to log in to network resources from remote locations by using a one-time password (OTP). Client software is only available through the App Store and must be used with the HOTPin server application to generate OTPs. This app is available for iPhone, iPad, and iPod touch running iOS 8 and higher.