Welcome!
To use the personalized features of this site, please log in or register.
If you have forgotten your username or password, we can help.
|
 |
Secure Identification and QKD in the Bounded-Quantum-Storage Model
| |
|
Secure Identification and QKD in the Bounded-Quantum-Storage Model
Ivan B. Damgård1 , Serge Fehr2 , Louis Salvail1 and Christian Schaffner2 
| (1) |
BRICS, FICS, Aarhus University, Denmark |
| (2) |
CWI Amsterdam, The Netherlands |
Abstract
We consider the problem of secure identification: user U proves to server S that he knows an agreed (possibly low-entropy) password w, while giving away as little information on w as possible, namely the adversary can exclude at most one possible password for each execution of the scheme. We propose
a solution in the bounded-quantum-storage model, where U and S may exchange qubits, and a dishonest party is assumed to have limited quantum memory. No other restriction is posed upon
the adversary. An improved version of the proposed identification scheme is also secure against a man-in-the-middle attack,
but requires U and S to additionally share a high-entropy key k. However, security is still guaranteed if one party loses k to the attacker but notices the loss. In both versions of the scheme, the honest participants need no quantum memory, and
noise and imperfect quantum sources can be tolerated. The schemes compose sequentially, and w and k can securely be re-used. A small modification to the identification scheme results in a quantum-key-distribution (QKD) scheme,
secure in the bounded-quantum-storage model, with the same re-usability properties of the keys, and without assuming authenticated
channels. This is in sharp contrast to known QKD schemes (with unbounded adversary) without authenticated channels, where
authentication keys must be updated, and unsuccessful executions can cause the parties to run out of keys.
Fulltext Preview (Small, Large)
 References secured to subscribers.
|
|
|
|
|
|