Infrastructure

The core components of the GuardTime technology are its Grid, Calendar and Publishing.

The GuardTime Grid, i.e. a hierarchical distribution and aggregation grid to provide the integrity service, consists of layers that collect the timestamping and verification requests from the Gateways below and that pass only a fixed size summary of the requests on to the level above. This ensures that the load of any server in any layer only depends on the number of direct subordinate servers, not on the total number of servers in the lower indirect layers, nor the number of requests issued by those indirect subordinates. This in turn means that the service is infinitely scalable: to be able to issue more timestamps only more gateways have to be added to the Grid, yet the load on the core servers does not increase. There is no bottleneck in the system.

The second core component is GuardTime Calendar. Every second a new entry that summarizes all timestamping requests accumulated during the second is added to the calendar and linked to the summaries of past seconds. The linking information is then distributed down the Grid back to the gateway level where it is included in all the timestamps issued for that second.

Thirdly, the current state of the calendar is published in the newspapers as the Integrity Code. Any timestamp issued prior to the creation of the Integrity Code can be linked to it, thus proving the age and integrity of the timestamp. The process is based only on summarizing data from the level below on each step. There is no secret key that could be compromised and thus there is no risk that a timestamp that is valid today could become worthless in the future due to some security incident.