Security Analysis of a Distributed Common Secret Generation Procedure

In a distributed scheme allowing any number of members to compute a commonsecret without revealing individual secret was proposed. We present asecurity weakness of this protocol. In doing so, we show that any twomembers can collude and obtain the secret contributed by middle memberin generating the common secret.Journal of Cryptology</i

Pointer og lektionsstudier

Kommentar til artiklen “Når pointer styrer matematikundervisning” i MONA, 2012(3

A Distributed Shared Key Generation Procedure Using Fractional Keys

We present a new class of distributed key generation and recoveryalgorithms suitable for group communication systems where the groupmembership is either static or slowly time-varying, and must be tightlycontrolled. The proposed key generation approach allows entities whichmayhave only partial trust in each other to jointly generate a shared keywithout the aid of an external third party. The group collectivelygenerates and maintains a dynamic group parameter, and the shared key isgenerated using a strong, one-way function of this parameter. This schemealso provides perfect forward secrecy. The validity of key generation canbe checked using verifiable secret sharing techniques. The key retrievalmethod does not require the keys to be stored in an external retrievalcenter. We note that many Internet-based applications may have theserequirements. Fulfillment of these requirements is realized through theuse of fractional keys--a distributed technique recently developed toenhance the security of distributed systems in a non-cryptographicmanner

How to Explain Modern Security Concepts to your Children

International audienceAt the main cryptography conference CRYPTO in 1989, Quisquater et al. published a paper showing how to explain the complex notion of zero-knowledge proof in a simpler way that children can understand. In the same line of work, we present simple and intuitive explanations of various modern security concepts and technologies, including symmetric encryption, public key encryption, homomorphic encryption, intruder models (CPA, CCA1, CCA2) and security properties (OW, IND, NM). The explanations given in this paper may also serve in demystifying such complex security notions for non-expert adults

RSA-kryptering med diskusjon om bruk av det i skolen

Masteroppgaven gir en grunnleggende introduksjon av RSA kryptering, og angrep på RSA kryptering. Vi presenterer, modulær aritmetikk, tallteorien som er nødvendig for å forstå RSA kryptering, og en generell innføring i hva kryptografi er, og introduserer ulike prinsipper for kryptering. Vi ser på de matematiske prinsippene bak RSA-systemet, og viser hvorfor det er ’sikkert’. Vi ser på måter for å oppnå suksessfulle ’real life’ angrep på RSA-systemet. Tilslutt sees det på hvordan dette passer inn i undervisningen i skolen

The elements of cryptography in teaching

Kriptografija je znanstvena disciplina koja proučava metode slanja poruka u obliku u kojemu ih može pročitati samo osoba kojoj su namijenjene. U ovom su radu navedeni elementi povijesti kriptografije te predstavljene zanimljive metode šifriranja i dešifriranja. Neke od tih metoda prilagođene su učenicima osnovnih škola, a moguće ih je provesti u redovnoj ili dodatnoj nastavi matematike. Uključivanje elemenata kriptografije može obogatiti nastavu, dati joj dinamičnost i uzbudljivost, ali i potaknuti kreativnost, znatiželju i motiviranost kod učenika. Ideja rada prikazati je kako na zanimljiv način približiti učenicima kriptografiju, što je i provedeno s učenicima razredne i predmetne nastave. Radionica je provedena i sa studentima Fakulteta za odgojne i obrazovne znanosti u Osijeku, budućim učiteljima, s ciljem upoznavanja s mogućnostima uvođenja kriptografskih sadržaja u redovnu ili dodatnu nastavu matematike.Cryptography is a scientific discipline that studies the methods of sending messages in a form that can only be read by the person they are intended for. In this paper elements of cryptographic history are presented as well as interesting methods of encryption and decryption. Some of the methods are adjusted for primary school students and can be implemented in both regular and additional (advanced) mathematics class. The use of cryptographic elements may enrich teaching and contribute to its dynamics and excitement, but also stimulate creativity, curiosity and motivation among students. The idea of the paper is to present cryptography in an interesting way in classes, which was tested among primary school students. The workshop was also conducted with students of the Faculty of Education in Osijek, i.e. future teachers, with the aim to learn about different possibilites of including a cryptographic content into regular or additional (advanced) mathematics classes

The elements of cryptography in teaching

Kriptografija je znanstvena disciplina koja proučava metode slanja poruka u obliku u kojemu ih može pročitati samo osoba kojoj su namijenjene. U ovom su radu navedeni elementi povijesti kriptografije te predstavljene zanimljive metode šifriranja i dešifriranja. Neke od tih metoda prilagođene su učenicima osnovnih škola, a moguće ih je provesti u redovnoj ili dodatnoj nastavi matematike. Uključivanje elemenata kriptografije može obogatiti nastavu, dati joj dinamičnost i uzbudljivost, ali i potaknuti kreativnost, znatiželju i motiviranost kod učenika. Ideja rada prikazati je kako na zanimljiv način približiti učenicima kriptografiju, što je i provedeno s učenicima razredne i predmetne nastave. Radionica je provedena i sa studentima Fakulteta za odgojne i obrazovne znanosti u Osijeku, budućim učiteljima, s ciljem upoznavanja s mogućnostima uvođenja kriptografskih sadržaja u redovnu ili dodatnu nastavu matematike.Cryptography is a scientific discipline that studies the methods of sending messages in a form that can only be read by the person they are intended for. In this paper elements of cryptographic history are presented as well as interesting methods of encryption and decryption. Some of the methods are adjusted for primary school students and can be implemented in both regular and additional (advanced) mathematics class. The use of cryptographic elements may enrich teaching and contribute to its dynamics and excitement, but also stimulate creativity, curiosity and motivation among students. The idea of the paper is to present cryptography in an interesting way in classes, which was tested among primary school students. The workshop was also conducted with students of the Faculty of Education in Osijek, i.e. future teachers, with the aim to learn about different possibilites of including a cryptographic content into regular or additional (advanced) mathematics classes