B2ACCESS is a federated cross-infrastructure authorisation and authentication framework that enables single sign-on access to EUDAT services. It supports authentication via users' primary identity providers like Google, is integrated with EduGain to support identities from universities and research institutions, and can integrate with any EUDAT or other service using SAML, OAuth2, or X.509. B2ACCESS provides unique and persistent EUDAT user IDs and allows service managers to specify authorisation decisions.