We discuss the availability questions that arise when digital time stamps are used for preserving the evidentiary value of electronic documents. We analyze the time-stamping protocols known to date and point out some weaknesses that have not been addressed so far in scienti c literature. Without addressing and solving them, any advantage of the linkage-based protocols over the hash-and-sign tim...

This paper describes the results of a research activity conducted cooperatively by an academic and an industrial party. It presents a practical solution for and an experience in the implementation of time stamping services and their exposition to the Internet for inter-enterprise integration. State-of-the-art time stamping algorithms and crucial issues related to their practical implementation ...

This paper presents a web-based architecture for providing digital time stamping services. Time stamping services are typically divided into schemes which rely on unconditionally trusted Time Stamping Authorities (TSAs) and schemes which do not, namely the so called linking schemes. The proposed architecture relies on a multi-tier structure. The middle-tier exposes digital time stamping functio...

The aim of a time-stamping system is to prove the existence of a digital document at a particular time in the past. Implemented time-stamping systems are generally based on a centralized server model. However, the unique server may represent a weakness for the system. In this paper, we propose a distributed time-stamping scheme which is more robust against a denial of service attack. Our protoc...

In order to improve the utilization of materials, improving stamping cage processing methods, the single row tapered roller bearing cage is improved from structural strength, puts forward whole stamping cage a type of structure. Use ANSYS finite element analysis to the different structure and the thickness cage. Get the stress contours of the cage, based on equal strength design principles. Get...

Using an inverse analysis technique, the heat transfer coefficient on the die-workpiece contact surface of a hot stamping process was evaluated as a power law function of contact pressure. This evaluation was to determine whether the heat transfer coefficient on the contact surface could be used for finite element analysis of the entire hot stamping process. By comparing results of the finite e...

To establish that a document was created after a given moment in time, it is necessary to report events that could not have been predicted before they happened. To establish that a document was created before a given moment in time, it is necessary to cause an event based on the document, which can be observed by others. Cryptographic hash functions can be used both to report events succinctly,...

In current proxy signature schemes, an original signer delegates her signing capability to a proxy signer, and then the proxy signer can sign messages on behalf of the original signer. Although these schemes have succeeded in proxy delegations, they share a common problem. That is, a verifier cannot ascertain that a proxy signature was signed by the proxy signer during the valid delegation peri...

Regardless of genome polarity, intermediaries of complementary sense must be synthesized and used as templates for the production of new genomic strands. Depending on whether these new genomic strands become themselves templates for producing extra antigenomic ones, thus giving rise to geometric growth, or only the firstly synthesized antigenomic strands can be used to this end, thus following ...