Openness is the becoming more crucial feature of science. Science is to be open because of healthiness of science itself and its public relationship. Openness in science is not only papers but also data now. Scholarly communication should adapt to the openness of papers and data in science. It is a long experience for openness of papers, i.e., open access of papers, but openness of data is relatively new and more challenging since data is diverse in contents and quantity and manifold in use. One of the key technology for sharing papers and data is identifier. Identifiers can remove ambiguity of digital objects and their attributions, realize smarter use of data, and make more linkages to other information. DOI (Digital Object Identifier) is the most successful identifiers in this area, which is now extending their target to data. Japan Link Center (JaLC) now starts the experimental use of DOI for data. The other identifier to be noted is ORCID (Open Researcher and Contributor Identifier), which is designed and used for identifying researchers worldwide. Embeding these idenfiers in metadata can make more suitable scholarly commucation to openness of science.