28,883 reputation
453109
bio website bolet.org/~pornin
location Quebec City, Canada
age 38
visits member for 2 years, 9 months
seen 15 mins ago

Cryptographer, programmer in several languages (C, Java, several assemblies, Pascal, Forth...). I also have a life.


Dec
18
answered What is the difference between CSPRNG and PRNG?
Dec
18
awarded  Nice Answer
Dec
18
comment Multi-party encryption algorithm
Well, you do not need to renew the group key if someone merely exits. You need to renew the group key only when you want a former group member to become unable to read subsequent messages -- i.e. not really when someone decides to get some sleep; you renew the key when you want to evict a group member. This should be as frequent as banning/kicking participants (i.e. quite rare).
Dec
18
answered What is the best (thoroughly covering) textbook for application of LFSRs in cryptography?
Dec
18
answered Multi-party encryption algorithm
Dec
17
answered Diffie-Hellman insecure on addition modulo $n$
Dec
17
answered Calculation of time to crack SHA-256 hash
Dec
17
answered Why can an RSA signature be authenticated ONLY with the signer's public key?
Dec
16
comment Advantages of bilinear map
Yes, that's it: no known way with currently known pairings and curve types.
Dec
16
comment Advantages of bilinear map
Note that depending on what you want out of the pairing, you cannot necessarily use just any kind of curve. $G_1$ and $G_2$ of size $p$ prime, a computable one-way isomorphism from $G_1$ to $G_2$, easy hashing into $G_2$: you cannot have all three characteristics simultaneously.
Dec
16
answered Advantages of bilinear map
Dec
9
awarded  Enlightened
Dec
9
awarded  Nice Answer
Dec
4
awarded  Famous Question
Nov
30
awarded  Populist
Nov
21
awarded  Enlightened
Nov
21
awarded  Nice Answer
Nov
15
comment Google is using RC4, but isn't RC4 considered unsafe?
Actually the answer still fits. An attack which requires spying on 16 millions of successive connections is still not practical: it can be demonstrated in lab conditions, but not in the field. Though the "security margin" is indeed not very large.
Nov
15
awarded  Nice Answer
Nov
12
awarded  Nice Answer