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bio website github.com/CodesInChaos
location Frankfurt, Germany
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visits member for 3 years, 1 month
seen 32 mins ago

Jul
3
comment Construct a random permutation from a random function?
If this is a practical problem, you should take a step back and describe your actual requirements.
Jul
3
comment Construct a random permutation from a random function?
Since a truncation of a PRF is still a PRF, you can trivially use the above construction where you truncate the PRF to N/2.
Jul
2
reviewed Approve suggested edit on cbc-mac tag wiki
Jul
2
reviewed Approve suggested edit on cbc-mac tag wiki excerpt
Jul
2
reviewed Approve suggested edit on cfb tag wiki excerpt
Jul
2
reviewed Edit suggested edit on cfb tag wiki
Jul
2
revised cfb wiki description
edited body
Jul
2
reviewed Approve suggested edit on ofb tag wiki
Jul
2
reviewed Approve suggested edit on ofb tag wiki excerpt
Jul
2
comment Using single EC cert/keying material to derive symmetric encryption key (for storage)?
Using asymmetric encryption is rather silly if the target is yourself. It's easier and stronger to use a symmetric secret for that. Can't you derive the P521 private key and the AES key from the same master key? That'd be a strong an clean solution.
Jul
2
comment ECDH VS. DH benchmarking in JAVA
BC uses affine coordinates (at least the implementation I looked at, perhaps it offers multiple), which are really slow for most curves. Optimized implementations should be 10-20 times as fast as BC.
Jul
1
comment How much stronger is RSA-2048 compared to RSA-1024?
@woliveirajr RSA-1024 is far weaker than that. AFAIK it's currently borderline feasible to break it for state level adversaries with a few billion to spend. If it's not breakable now, 10 years from now it should be.
Jul
1
comment What does NSA mean by 'Analyzable'?
The algorithms are similar to existing blockciphers, so cryptographers know how to analyze them. Being easy to analyze them is a good thing, because it becomes less likely that somebody suddenly find a new and much better attack.
Jul
1
revised RSA by hand - did I do something wrong? (c = m on encryption)
added 24 characters in body
Jul
1
reviewed Approve suggested edit on Seemingly simple decryption question
Jun
30
comment Block cipher with key longer than block size
Related questions AES Key Length vs Block Length and AES key/ciphertext space sizes
Jun
30
comment Block cipher with key longer than block size
This will likely be the case for some messages (even if the key is a shorter than the block size), but not for all of them. For a good block cipher for any key-pair $k_0 \neq k_1$ almost all messages will encrypt differently.
Jun
30
comment Why use variable p, q, g for Diffie-Hellman?
@RickyDemer Hm? Standard groups are random Schnorr groups. The only difference is that they're used by many people.
Jun
30
comment Why use variable p, q, g for Diffie-Hellman?
IMO fixing the group is a good idea. If I were to use finite-field based DH I'd use a standard group, just like I use standard elliptic curves. There are minor advantages in having your own group, but IMO the added complexity isn't worth it.
Jun
29
answered What type of groups does Microsoft's U-Prove use (Schnorr… etc?)