The Remote Signing Service (RSS) is Siemens' implementation of the Cloud Signature Consortium (CSC) API. The service enables its clients, CSC compliant Signature Applications to remotely sign documents when running on devices like smart phones, that themselves don't hold the signing certificates with their associated private keys.
This implementation provides Sole Control Assurance Level (SCAL) 2 in that it binds the hash to be signed to the Signature Activation Data (SAD) obtained during authorization.

This is the entry point of Siemens RSS.