10,847 reputation
12455
bio website github.com/CodesInChaos
location Frankfurt, Germany
age
visits member for 3 years, 8 months
seen 9 hours ago

19h
comment Is it safe to encrypt random data using ECB mode?
Can't answer that without context. But there is one thing all the modes you mentioned lack: Integrity checks/MACs.
21h
reviewed Leave Closed Who are cryptography programmers responsible to?
21h
revised Who are cryptography programmers responsible to?
rolled back to a previous revision
21h
reviewed Reviewed Is it possible to match encrypted documents using user-defined search terms?
21h
comment Is it possible to match encrypted documents using user-defined search terms?
Could you describe how you realized that encrypted search and what security trade-offs you made?
1d
comment Is there any pattern in points on EC?
Even if you're given a compressed point, i.e. you don't know y, you can still check if x^3+ax+b is a square. This can be avoided by either randomly choosing a point from the curve or its twist (with the correct probabilities) or using something fancy, like elligator.
Mar
27
comment Can anyone explain how IV(Initial vector ) are chosen in GCM and in CBC MAC in detail?
With CBC MAC you need a fixed IV, such as the all-zero value.
Mar
27
comment Can anyone explain how IV(Initial vector ) are chosen in GCM and in CBC MAC in detail?
With CBC encryption you need an unpredictable value, typically chosen as random 128 bit value, with GCM you need a unique value.
Mar
27
comment AES or Serpent-Twofish-AES
If AES is the weakest point of your setup, you've done a stellar job.
Mar
27
comment How efficient is the error correcting code?
What are you trying to achieve? And what exactly do you mean by "error correcting code"?
Mar
27
comment Can I construct a zero-knowledge proof that I solved a Project Euler problem?
Checking if you have the same answer as somebody else is the Socialist millionaire problem.
Mar
26
comment Blum primes [x=3(mod 4)] zero knowledge proof?
"I can, without revealing factors, show that n has two prime factors" -- how? I'm not aware of any way to do this. Using MPC to jointly produce a modulus is the approach that comes closest to achieving this.
Mar
26
revised NTRU Encryption
deleted 6 characters in body
Mar
25
comment Are modes of operation algorithms practical?
Kerckhoffs's principle
Mar
25
comment Now that quantum computers have been out for a while, has RSA been cracked?
@MichaelJonathanSimpson When you're worried about quantum computers, larger RSA keys won't offer much peace of mind. The number of required ideal qbits is linear in the key size. With error correction that increase might be steeper, but still not that big. Once a QC can factor a 2048 bit key it will probably only be a few years to factoring a 4096 bit key.
Mar
25
comment Cycles in SHA256
With a blockcipher (which is a permutation), the cycle length would be around $2^{255}$ with a hash the cycle length is around $2^{128}$. But of course these are just statistical values and both shorter and longer cycles exist.
Mar
24
reviewed Satisfactory Additional Data in AEAD (Chacha20-poly1305 libsodium)
Mar
23
comment What is the best hash for HMAC?
There are only two significant SHA-2 variants, SHA-256 and SHA-512. All the other variants only differ by truncation and have different IVs.
Mar
23
comment Is it safe to use PBEWithMD5AndDES?
If this is really DES and not 3DES then it's very weak.
Mar
22
comment Difference between the TLS cipher suites?
Nobody uses DSS suites/certificates. If you want better performance, go with the elliptic curve equivalent, ECDHE_ECDSA