Techniques of data authentication in a distributed computing system are disclosed herein. One example technique includes receiving a request for performing an operation along with a data package that includes a security token, a first digital signature of the security token generated using an ephemeral private key, and an ephemeral public key with a second digital signature generated using a master private key stored at a secure location. The example technique can also include initially validating the second digital signature using a public key corresponding to the master private key, and upon validating the second digital signature, validating the first digital signature of the security token using the ephemeral public key included in the data package. Upon validating that the first digital signature of the security token, the request can be authenticated, and the requested operation can be performed.