13,267 reputation
32867
bio website paul-ebermann.tumblr.com
location Berlin, Germany
age
visits member for 3 years, 1 month
seen yesterday

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:


Apr
18
comment How can I convert numbers into prime numbers?
Welcome to Cryptography Stack Exchange. From your answer, it seems like you have some more needs which are not clearly stated in the question. Maybe you could expand your question a bit?
Apr
18
comment Using Stream Cipher as CSPRNG
@StephenTouset The "outputs won't repeat" distinguisher is not universal for stream ciphers, I think, just for counter mode block ciphers or similar stuff. E.g. if you use a stream cipher build from a PRF in CTR mode, it will repeat just as often as expected for a true random stream.
Apr
16
comment The relationship between the key length and encrypt time in Xor algorithm?
Could you elaborate a bit what your "encryption algorithm using the XOR method" is exactly? For an one-time pad, the key length should be as much as the message length, so I suppose you are using something with repeated key?
Apr
9
awarded  Revival
Apr
2
awarded  Popular Question
Mar
30
comment Why the need to hash before signing small data?
Hmm, while this corrects some mistakes in the question, it doesn't really answer the underlying question: Would ECDSA be safe for small messages if we omitted the hashing step?
Mar
30
revised Is it possible to weaken a bitcoin private key by “using” it elsewhere?
deleted 373 characters in body
Mar
26
comment How useful is NIST's Randomness Beacon for cryptographic use?
Actually, an insider potentially could know these strings even longer ahead, assuming a predictable internal source.
Mar
23
comment Questions about hash functions
It looks like this would contradict the meaning of "secure hash", but I'm not sure how to formally prove it from the usual hash properties (collision/preimage/second preimage resistance)
Mar
19
comment Difference RSA keypair creation openSSL and openPGP?
@humanityANDpeace If you think this answer answered your question, please use the check mark button beside it to mark it as "accepted".
Mar
17
comment Why does Openssh use only SHA1 for signing and verifying of digital signatures?
Actually, the list of registered key exchange method names contains some with SHA-256.
Mar
17
comment Why does Openssh use only SHA1 for signing and verifying of digital signatures?
There is a MAC algorithm spec for SHA-2 in RFC 6668.
Mar
17
comment Why does Openssh use only SHA1 for signing and verifying of digital signatures?
I suppose that most of the SSH protocol is older than SHA-2, and nobody bothered to add new key exchange algorithms with SHA-2 to it.
Mar
17
comment Hash Based Encryption (fast & simple), how well would this compare to AES?
This exact algorithm you are proposing was already discussed at Is SHA-256 secure as a CTR block cipher?.
Mar
16
revised distribution for a subset of md5
edited tags
Mar
15
comment counter to indicate hotp count
Your server still has to make sure that the counter number only ever goes upward, to avoid replay attacks.
Mar
15
comment Trying to calculate the strength of a Bitcoin brain wallet created with a custom diceware password
You calculated the attackers worst case duration ... average case is half of this.
Mar
15
revised Trying to calculate the strength of a Bitcoin brain wallet created with a custom diceware password
formatting
Mar
15
answered Are there use cases where a signature itself needs to be signed?
Mar
15
answered Reusing AES-CTR Keys and IVs for File Encryption