Podpisi brez možnosti zanikanja

diplomsko delo

Bor Brecelj (Author), Aleksandar Jurišić (Mentor)

Abstract

V nekaterih situacijah ni zaželjeno, da lahko kdorkoli preveri veljavnost digitalnega podpisa. Podpisi brez možnosti zanikanja to dosežejo tako, da mora pri preverjanju podpisa sodelovati tudi podpisnik. Za preverjanje podpisa potrebujemo potrditveni protokol, s katerim dokažemo veljavnost našega podpisa, in zavrnitveni protokol, s katerim lahko dokažemo, da podpis ni naš. Poleg varnostne zahteve, da nihče ne more ponarediti podpisa, moramo dodati še zahtevo, da iz podpisa ni mogoče ugotoviti njegove veljavnosti brez sodelovanja podpisnika. Za oba protokola mora veljati, da sta dokaza brez razkritja znanja. Predstavili bomo vse te varnostne zahteve in navedli dva primera shem za podpis brez možnosti zanikanja skupaj z dokazi varnostnih zahtev.

Keywords

digitalni podpisi;kriptografija;podpisi brez možnosti zanikanja;računalništvo;računalništvo in informatika;računalništvo in matematika;interdisciplinarni študij;univerzitetni študij;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2020
Typology:	2.11 - Undergraduate Thesis
Organization:	UL FRI - Faculty of Computer and Information Science
Publisher:	[B. Brecelj]
UDC:	004(043.2)
COBISS:	32203011
Views:	1065
Downloads:	136
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Undeniable signatures
Secondary abstract:	While anybody can verify usual digital signatures, in some cases the signer wants the power to decide who can check his signature. It is the role of undeniable signatures to make this possible. The signer can prove the validity of his signature by using a so called confirmation protocol. However, there is also a need for a (disavowal) protocol the signer uses to deny his authorship of a particular signature. There are two main security requirements for undeniable signatures: first, nobody can forge a signature and, second, this signature must be indistinguishable from a randomly chosen one. Therefore, nobody can verify a signature without the signer's cooperation. For security reasons it is also important that both protocols are zero-knowledge proofs. In this thesis we present security requirements and provide two examples of an undeniable signature scheme. Finally, we give proofs of unforgeability and invisibility.
Secondary keywords:	digital signatures;cryptography;undeniable signatures;computer science;computer and information science;computer science and mathematics;interdisciplinary studies;diploma thesis;
Type (COBISS):	Bachelor thesis/paper
Study programme:	1000407
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Fak. za računalništvo in informatiko
Pages:	53 str.
ID:	12042783