13,781 reputation
33472
bio website paul-ebermann.tumblr.com
location Berlin, Germany
age
visits member for 3 years, 8 months
seen 23 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
19
comment Deciphering text encrypted with a changing cipher
It is not exactly CFB (for $k > 1$), as it doesn't really use blocks. But I guess the proof might be transferable (and might need a large enough $k$).
Mar
18
comment Composition of non-perfect encryption keys
Please note that composing encryption functions is usually not the same as doing some operation on their keys. Also, your meaning of key seems to be as a random variable (which has a distribution), where I would usually think of an individual key.
Mar
18
revised Composition of non-perfect encryption keys
formatting
Mar
18
comment MAC in SSH packet encryption, benefits to not including it?
It allows an attacker to modify your data. If you are an attacker, this would be an advantage ;-) (The MAC is not there for authentication of the other end, but to make sure that an attacker doesn't modify your data.)
Mar
17
comment What practical uses can random hash collisions be put to?
Could you detail how one would use this machine (as described in the question, it is actually a random-first-preimage-machine) to sign different jar files or similar non-random data? Or do you simply want to use the machine as a RNG?
Mar
15
comment Why does consecutive permutations or consecutive substitutions not enhance security?
@fgrieu I guess this could be meant to apply to unkeyed permutations/substitutions only?
Mar
15
comment Encryption with a known plaintext
And if using a single block message (and zero key), your scheme is actually CBC-MAC, of which CMAC is a modification. (CMAC XORs the plaintext with some derived key before encrypting it.)
Mar
8
comment Can IGE mode be parallelized?
Hi, welcome to cryptography Stack Exchange. Your message was migrated here from Security Stack Exchange, because it is about a mode of operation, and better answered here. Please create an account here using the same Mail address as you used as Security SE, to be able to claim your question, possibly edit it, and accept an answer.
Mar
8
revised Can IGE mode be parallelized?
make decryption a bit more clear.
Mar
8
revised Can IGE mode be parallelized?
rewording to spell the mode name out
Mar
8
comment If a cipher has key length shorter than plaintext, then it is not perfectly secure
Perfect secrecy is not about any time bound attacker. The point is not that brute force takes some smaller number of steps, but that trying all keys gives you less than all messages with a smaller key size.
Mar
8
comment how to integrate 2-3 algorithms to encrypt large data fastly and securely insted using AES?
What is your actual question here?
Feb
25
revised How to communicate by email with forward secrecy and deniability?
deleted 1 character in body
Feb
23
comment Why is AES resistant to known-plaintext attacks?
Also, if you want to discuss more of this, maybe do this in Chat and not as comments to my answer.
Feb
23
comment Why is AES resistant to known-plaintext attacks?
@Pacerier Ricky likes to add spaces into his comments to "improve" their visual appearance, and does this with TeX (MathJax) formatting. In your inbox, this doesn't work, so the $ and \; (a kind of space) show up. (I think this is not worth the hassle, and doesn't even work with every browser/screen-size/font size combination.)
Feb
12
comment Is the complexity of Caesar (shift) ciphers “n * n!”?
Please note that "decryption" usually means an algorithm which knows the key. And knowing the key, you should be able to decrypt a text in O(length of text).
Feb
8
comment Is $f(x)\oplus x$ a one-way function?
Of course, this is only a counter-example if one-way functions exist at all.
Feb
6
awarded  Notable Question
Jan
13
revised How to find the factors of the modulus?
edited tags
Jan
9
revised Are there any known inverse hash lookups for the zero string?
null → zero