13,566 reputation
33272
bio website paul-ebermann.tumblr.com
location Berlin, Germany
age
visits member for 3 years, 5 months
seen 51 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:


Oct
11
revised How does MD5 process text which is shorter than 512 bits
added 7 characters in body
Oct
10
revised How does a chosen ciphertext attack work, with a simple example?
remove the "there is no such thing", as it comes from before the migration.
Oct
6
comment What does “nonlinear mapping” mean?
Welcome to Cryptography Stack Exchange. After your edit, it seems that we only can say "yes" or "no" (and I would say "yes"). Maybe you could move the answering part (after the sentence "I'm not sure if I understand this correct") into an actual answer?
Oct
6
comment Is there a string that's hash is equal to itself?
A rotation itself doesn't prevent things mapping to itself, e.g. (on a byte-level) rotating 11111111 by any amount still gives 11111111.
Oct
6
comment Skein or Keccak stream cipher construction
The stream cipher part is essentially counter mode with a hash function.
Oct
1
awarded  Refiner
Sep
30
comment Homomorphic encryption based on XOR
yes, typo (now fixed). Yes, but the "field of order $2^q$" doesn't have the same addition (or multiplication) as the ring $\mathbb Z/_{2^q \mathbb Z}$, so you shouldn't talk about "$\bmod 2^q$" here. (It is now clearer after your edit.)
Sep
30
awarded  Explainer
Sep
30
comment Homomorphic encryption based on XOR
(Actually, $x + y \bmod 2^q$ is not the same operation as $x \oplus y$ for $q > 1$.
Sep
30
comment Homomorphic encryption based on XOR
But for $p = 2^q$, we have $(a \oplus d) \oplus (b \oplus d) = (a \oplus b) \neq (a \oplus b) \oplus d$ – or do you want to define $x \boxplus y := x \oplus y \oplus d$?
Sep
28
comment Why does key generation take an input $1^k$, and how do I represent it in practice?
Why can't we select the $n^{\text {th}}$ circuit with the usual binary form of $n$?
Sep
25
awarded  Nice Answer
Sep
24
awarded  Autobiographer
Sep
13
comment Last Round in DES
You can incorporate the last swap into the final permutation.
Sep
12
revised Chi-Squared Step of Vigenere Cipher Decryption
formatting
Sep
12
revised How can AES be considered secure when encrypting large files?
edited tags
Sep
12
revised Are there cryptographic hash functions with homomorphic properties?
distributive → homomorphic
Sep
12
comment Are there cryptographic hash functions with homomorphic properties?
Yes, "homomorphic" property is the right word.
Sep
12
comment Why are we advising PKI if we know that quantum computers will break them?
You have some mixup of the terms here. Also, how do you know what the future of quantum computing is?
Sep
7
comment Change Salt when Changing Password?
If there is an internal attacker (like a rouge sysop in a bigger team – not enough to change the software, but with access to the password database – or simply stolen backups), it might be feasible to have several breaches in sequence, which might not even be noticed.