Based on some limited debugging on Windows 10 1809, it appears that Windows does not require the owner auth. Running the application "as administrator" and providing an empty TPM2B_AUTH (with auths[0].sessionHandle = TPM2_RW_PW) allows me to successfully call functions like... Tss2_Sys_NV_DefineSpace Tss2_Sys_NV_UndefineSpace Tss2_Sys_NV_ReadPublic Tss2_Sys_NV_Write Tss2_Sys_StartAuthSession Tss2_Sys_PolicySecret Tss2_Sys_Create Tss2_Sys_FlushContext Tss2_Sys_PolicySecret Tss2_Sys_Load Tss2_Sys_EvictControl