- Tytuł:
- Sender-equivocable encryption schemes secure against chosen-ciphertext attacks revisited
- Autorzy:
-
Huang, Z.
Liu, S.
Qin, B.
Chen, K. - Powiązania:
- https://bibliotekanauki.pl/articles/330140.pdf
- Data publikacji:
- 2015
- Wydawca:
- Uniwersytet Zielonogórski. Oficyna Wydawnicza
- Tematy:
-
sender equivocable encryption
chosen ciphertext attack
cross authentication code - Opis:
- Fehr et al. (2010) proposed the first sender-equivocable encryption scheme secure against chosen-ciphertext attacks (NCCCA) and proved that NC-CCA security implies security against selective opening chosen-ciphertext attacks (SO-CCA). The NC-CCA security proof of the scheme relies on security against substitution attacks of a new primitive, the “cross-authentication code”. However, the security of the cross-authentication code cannot be guaranteed when all the keys used in the code are exposed. Our key observation is that, in the NC-CCA security game, the randomness used in the generation of the challenge ciphertext is exposed to the adversary. Based on this observation, we provide a security analysis of Fehr et al.'s scheme, showing that its NC-CCA security proof is flawed. We also point out that the scheme of Fehr et al. encrypting a single-bit plaintext can be refined to achieve NC-CCA security, free of the cross-authentication code. Furthermore, we propose the notion of “strong cross-authentication code”, apply it to Fehr et al. 's scheme, and show that the new version of the latter achieves NC-CCA security for multi-bit plaintexts.
- Źródło:
-
International Journal of Applied Mathematics and Computer Science; 2015, 25, 2; 415-430
1641-876X
2083-8492 - Pojawia się w:
- International Journal of Applied Mathematics and Computer Science
- Dostawca treści:
- Biblioteka Nauki
Artykuł