193 reputation
5
bio website arrayboundserror.blogspot.com
location West, MS
age
visits member for 2 years, 6 months
seen Jan 3 at 17:07

For me, fun is taking a program, language, whatever and making it do things it's designer never envisioned it doing. It comes in handy when I'm asked to do something a little outside the norm as part of my job.


My day job


Dec
29
comment Can an RSA public key be generated without ever knowing the factors?
For what I'm thinking of, see the context I linked (IIRC down near the bottom).
Dec
28
asked Can an RSA public key be generated without ever knowing the factors?
Sep
16
asked Using SHA3 as an entropy pool
Jun
19
comment How hard is it to generate a partial RSA fingerprint collision?
@poncho point. That said, I'm assuming the SSH client is diligent enough to spot gratuitously weak keys, which requires the generation (I assume) of at least modestly sized primes, so you can't go to far down that path.
Jun
19
awarded  Commentator
Jun
19
comment How hard is it to generate a partial RSA fingerprint collision?
If it's assumed that finding the large primes is a major cost, then it would be reasonable to economize on them: i.e. generate $n$ reasonably sized primes and check all $\frac{n(n-1)}{2}$ combinations.
Jun
19
comment How hard is it to generate a partial RSA fingerprint collision?
Reading between the lines, anyone with more than a passing interest could forge 10-12 selected hex digits of a fingerprint. So if you are going to even bother looking you had better check at least 20.
Jun
18
comment How hard is it to generate a partial RSA fingerprint collision?
If you have money to throw at it, buying time on commercial VM service is a real option. I've heard real stories of academics running GNFS on Amazons S3. At ~0.6 USD/hr (aws.amazon.com/ec2/#pricing) and your guesses, that's $2^{42}$ to $2^{43}$ for 1k cash.
Jun
18
comment How hard is it to generate a partial RSA fingerprint collision?
See clarification.
Jun
18
revised How hard is it to generate a partial RSA fingerprint collision?
added 558 characters in body
Jun
18
asked How hard is it to generate a partial RSA fingerprint collision?
Jan
30
comment Can nesting different ciphers with different keys ever decrease security?
I guess then, the question should then be (and I'm not expecting an answer to this ): would it increase the complexity more for the attacker or the defender? -- As you point out, it given more surface area to attack but OTOH, it limits the value of any given attack as it limits the number of rounds that it would apply to.
Jan
28
comment Can nesting different ciphers with different keys ever decrease security?
@fgrieu: so you would never use a composed rounds cipher without careful analyses, but I haven't seen any suggestion that it would be inherently worse than a uniform round cipher.
Jan
28
awarded  Supporter
Jan
28
awarded  Editor
Jan
28
revised Can nesting different ciphers with different keys ever decrease security?
added 111 characters in body
Jan
28
comment Can nesting different ciphers with different keys ever decrease security?
I assume those modes are with respect to the block chaining and such. (And that is interesting and important information. +1) However, the problem I was thinking of is only with regards to the non-chained bare block cipher. (E.g. AES rather than AES-*.)
Jan
25
comment Designing a key expander out of ciphers
Yup, that looks correct to me un-trained eyes. OTOH the programmer in me sees the risk that comes from not having the second k change as well: if you somehow end up with an off-by-one error and generate "k prime -1", you are back where you started.
Jan
25
comment Designing a key expander out of ciphers
If cipher_1 is just xor, all the k primes will be exactly k. Or am I missing something?
Jan
24
awarded  Scholar