12,978 reputation
32764
bio website paul-ebermann.tumblr.com
location Berlin, Germany
age
visits member for 3 years
seen 58 mins ago

Don't fear to edit my posts: even if I have more reputation than you, I do make mistakes.

I'm now also a Moderator Pro Tempore (= until the first elections) at Cryptography Stack Exchange: feel free to come around and ask some cryptography questions.


My personal name is spoken as /ˈpawlo/ (IPA), in English this would be written similar to Powlo, I think (i.e. the vowels are ow and o), with an accent on the before-last syllable (which is the first in this case). It's the Esperanto form of my given name.

The photo shows my shadow, taken at night. My camera sometimes seems to forget all the other frequencies and only stores the green ones.

My current main private programming project is the game of fencing, an online abstract turn based strategy game. Implemented as a Java applet, using git as a version control system.


Some more links:


Mar
4
comment Is it possible to calculate the 'skeleton key' for DUAL_EC_DRBG? What would it take?
At least is is not that easy that everybody can do it, otherwise the skeleton key would already be public, and the Dual_EC_DRGB not only "potentially undermined by NSA", but actually undermined by everyone.
Mar
4
revised Is it possible to calculate the 'skeleton key' for DUAL_EC_DRBG? What would it take?
edited tags
Mar
4
comment Why is H(k||x) not a secure MAC construction?
@owlstead I added the information about SHA-2 and SHA-3 to the answer.
Mar
4
revised Why is H(k||x) not a secure MAC construction?
added 985 characters in body
Mar
1
comment What stops the Multiply-With-Carry Random Number Generator from being a Cryptographically Secure Pseudo-Random Number Generator?
I suppose the "mother of all RNGs" is mostly a historic description, not a quality one: many other RNGs came later and borrowed from its design.
Feb
21
comment ElGamal in private set intersection: how to handle negative numbers?
Moderator note: This answer was migrated from a merged duplicate question.
Feb
21
revised How secure is AES-256?
some grammar fixes
Feb
18
comment Partially-known-plaintext attack of a stream cipher based on modular arithmetic
Note: I deleted a bunch of comments which were obsolete after edits to the question.
Feb
17
revised Why hash or salt when signing?
added 1 characters in body
Feb
16
awarded  Nice Answer
Feb
12
revised Is Diffie-Hellman mathematically the same as RSA?
added 8 characters in body
Feb
11
comment Pseudo random permutation for arbitrary size domains
What you search is format-preserving encryption. It is generally slower than AES, though.
Feb
11
comment Complexity class of an idealised version of Bitcoin's proof-of-work (hashcash)?
This question is a duplicate of bitcoin.stackexchange.com/q/13796/488 on our sister site Bitcoin SE.
Feb
7
awarded  Pundit
Feb
1
comment Can you prove the existance of a PRG $G$ s.t. for each even $k$: $G(k)=G(k+1)$?
If a function $G$ has $G(k) = G(k+1)$ (and if $+$ is addition of natural numbers), then $G$ is a constant function, and I don't think this qualifies as a PRG.
Jan
21
comment Looking for alternative key stretching
Could you make your requirements a bit clearer? Do you mean that $f(f(x)) = f(x)$?
Jan
17
comment What does SSL use? RSA? El-Gamal? Elliptic curves?
@bobjandal The question (and the answer) is about SSL, not other crypto protocols like OpenPGP.
Jan
13
answered Why is the discrete logarithm problem assumed to be hard?
Jan
10
reviewed Approve suggested edit on private-set-intersection tag wiki
Jan
10
reviewed Approve suggested edit on private-set-intersection tag wiki excerpt