32,441 reputation
562124
bio website bolet.org/~pornin
location Quebec City, Canada
age 39
visits member for 3 years, 3 months
seen yesterday

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


Aug
13
answered How is SHA1 different from MD5?
Aug
12
comment linear computations over bilinear pairings
Two elements in a group are opposite to each other if their product is 1 (or their sum is 0, if you use an additive notation for the group).
Aug
12
answered linear computations over bilinear pairings
Aug
12
answered Security issues of a MAC-then-Encrypt-then-MAC approach?
Aug
11
awarded  Enlightened
Aug
11
awarded  Nice Answer
Aug
6
awarded  Nice Answer
Aug
4
comment Point addition equation in projective co ordinates
Yes, you get the same point at the end. That's the idea of non-unique coordinates: you have the choice of representation, but they all stand for the same curve point.
Aug
3
comment Is perfect-forward secrecy achieved with RSA?
One may note that SSL used to support ephemeral RSA keys. It was defined as part of the "RSA_EXPORT" cipher suites, in SSL 3.0 and TLS 1.0 (support was dropped in TLS 1.1). When an RSA_EXPORT cipher suite was chosen and the server's public key length was 513 bits or more, the server had to send a ServerKeyExchange message with a RSA key pair in it. I am not sure many SSL implementations supported it, though.
Aug
3
answered Point addition equation in projective co ordinates
Jul
15
comment Is RSA of a random nonce with no padding safe?
Using the rightmost (least significant) bits should be safe (the leftmost bits are a bit biased), but the argument is a bit more complex; using a hash function is safer.
Jul
12
awarded  Yearling
Jul
6
awarded  Pundit
Jun
19
awarded  Nice Answer
Jun
18
awarded  Enlightened
Jun
18
awarded  Nice Answer
Jun
16
comment AES VS PRNG+HASH+XOR
Well, don't forget that when you use a hash function as a stream cipher, you are actually trusting two "pieces of software": the hash function itself, and the construction which turns it into a stream cipher. Either may be subject to design and implementation weaknesses.
Jun
16
answered AES VS PRNG+HASH+XOR
Jun
15
answered TLS - sharing 1792 bits of unidirectional keys
Jun
15
revised Trial divisions before Miller-Rabin checks?
added 666 characters in body