Methods and apparatus for provisioning electronic Subscriber Identity Module (eSIM) data by a mobile device are disclosed. Processing circuitry of the mobile device transfers encrypted eSIM data to an embedded Universal Integrated Circuit Card (eUICC) of the mobile device as a series of data messages and receives corresponding response messages for each data message from the eUICC. The response messages from the eUICC are formatted with a tag field that indicates encryption and signature verification properties for the response message. Different values in the tag field indicate whether the response message is (i) encrypted and verifiably signed, (ii) verifiably signed only, or (iii) includes plain text information. Response messages without encryption are readable by the processing circuitry, and processing of the response messages, including forwarding to network elements, such as to a provisioning server are based at least in part on values in the tag field.