Introduction New Attack Extensions conclusion

Second Preimage

Description

Introduction New Attack Extensions conclusion Second Preimage Attacks on Dithered Hash Functions Elena Andreeva1 Charles Bouillaguet2 Pierre-Alain Fouque2 Jonathan J. Hoch3 John Kelsey4 Adi Shamir2,3 Sebastien Zimmer2 1K.U. Leuven, ESAT/COSIC, Leuven-Heverlee, Belgium 2École Normale Supérieure, Paris, France 3Weizmann Institute of Science, Rehovot, Israel 4NIST, Gaithersburg, MD, USA EUROCRYPT 2008

• given m1


• h1 h2 h3


• hash functions


• collision attack


• leuven-heverlee


• attack extensions


• functions

Sujets

• Antécédent (mathématiques)
• Hash function
• Collision attack

Informations

• Publié par: pefav
• Nombre de lectures: 20
• Langue: English

Extrait

IntroductionNewtAatkcxEetsnoisn

Second Preimage Attacks on Dithered Hash Functions

Elena Andreeva 1 Charles Bouillaguet 2 Pierre-Alain Fouque 2 Jonathan J. Hoch 3 John Kelsey 4 Adi Shamir 2,3 Sebastien Zimmer 2

1 K.U. Leuven, ESAT/COSIC, Leuven-Heverlee, Belgium

2 École Normale Supérieure, Paris, France

3 Weizmann Institute of Science, Rehovot, Israel

4 NIST, Gaithersburg, MD, USA

EUROCRYPT 2008

conclusion

1 6dM 2 s=M.H.t 1 )(MM(H= I .) 2 laeduces CollsioianttcaFkni 1 M=6 2 Mdnfi, 1 Mnevi ).M 2 H()=M 1 H( t.s.ocdn . 2 eS 2: /n iryt ackGeattimag-pre .sMd(H.tnevinfi,y sealricu =yM) de . I ruti:y n 2dIaeslce eattackG . Preimag

Iterated Hash Functions

n .:2ty

H:{0,1} ∗ 7→ {0,1} n

a

random oracle”.

behave

“like

Hash Functions Cryptanalysis

Should

enxtkEacttwANeonitcudortnIoinlcsucsnoisno

IntrodcuitonNewAttack

Iterated Hash Functions Hash Functions Cryptanalysis

Ext

H:{0,1} ∗ 7→ {0,1} n

Should behave “like a random oracle”.

nesions

Collision attackFindM 1 6=M 2 s.t.H(M 1 ) =H(M 2 ). Ideal security: 2 n/2 . Second-preimage attackGivenM 1 , findM 2 6=M 1 s.t. H(M 1 ) =H(M 2 ). Ideal security: 2 n . Preimage attackGiveny, findMs.t.H(M) =y. Ideal security: 2 n .

occnulisno

nIrtodcuitnoNewAttack

Iterated Hash Functions Hash Functions Cryptanalysis

Ext

H:{0,1} ∗ 7→ {0,1} n

Should behave “like a random oracle . ”

ensions

Collision attackFindM 1 6=M 2 s.t.H(M 1 ) =H(M 2 ). Ideal security: 2 n/2 . Second-preimage attackGivenM 1 , findM 2 6=M 1 s.t. H(M 1 ) =H(M 2 ). Ideal security: 2 n . Preimage attackGiveny, findMs.t.H(M) =y. Ideal security: 2 n .

occnlusion