Name
Abstract | ||
|---|---|---|
In this paper, we study the security of a practical randomness extractor and its application in the TLS standard. Randomness extraction is the first stage of key derivation functions since the secret shared between the entities does not always come from a uniformly distributed source. More precisely, we wonder if the Hmac function, used in many standards, can be considered as a randomness extractor? We show that when the shared secret is put in the key space of the Hmac function, there are two cases to consider depending on whether the key is larger than the block-length of the hash function or not. In both cases, we provide a formal proof that the output is pseudo-random, but under different assumptions. Nevertheless, all the assumptions are related to the fact that the compression function of the underlying hash function behaves like a pseudo-random function. This analysis allows us to prove the TLS randomness extractor for Diffie-Hellman and RSA key exchange. Of independent interest, we study a computational analog to the leftover hash lemma for computational almost universal hash function families: any pseudo-random function family matches the latter definition. |
Year | DOI | Venue |
|---|---|---|
2008 | 10.1145/1368310.1368317 | ASIACCS |
Keywords | Field | DocType |
hash function,hmac function,pseudo-random function family,rsa key exchange,underlying hash function,randomness extractor,pseudo-random function,universal hash function family,compression function,key space,key derivation function,tls,key exchange,pseudo random function,hmac,diffie hellman,secret sharing | Key derivation function,Hash-based message authentication code,Randomness extractor,Leftover hash lemma,Computer security,Computer science,Cryptographic hash function,Algorithm,Theoretical computer science,Randomness tests,Hash function,Hash chain | Conference |
Citations | PageRank | References |
24 | 0.96 | 12 |
Authors | ||
3 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Pierre-Alain Fouque | 1 | 1762 | 107.22 |
| David Pointcheval | 2 | 781 | 33.25 |
| Sébastien Zimmer | 3 | 205 | 9.29 |