CodesInChaos

less info
meta site favicon meta user | stack exchange network profile network profile
6,155 reputation
1927
bio website github.com/CodesInChaos
location Munich, Germany
age
visits member for 1 year, 11 months
seen 1 hour ago
stats profile views 112

1,190 Actions

suggestions reviews revisions comments badges posts accepts all
1h
 comment Can two cipher letters per plaintext letter easily defeat character frequency analysis?
Sounds like a homophonic substitution cipher.
11h
 comment Reverse engineering from known ID inputs and 19/20-digits outputs
If whoever wrote this knew what they were doing then they chose a secure 64 bit block cipher which you wouldn't be able to reverse without finding the key somewhere (for example in the source code)
11h
 reviewed Approve suggested edit on Hash function with values in a multiplicative group of prime order
1d
 comment Hash function with values in a multiplicative group of prime order
which group are you using?
1d
 reviewed Approve suggested edit on Can cryptography be used to hide routing information from the router?
1d
 reviewed Approve suggested edit on Anonymity in end-to-end encryption
Jun
15
 comment Security of authenticated encryption modes gcm & ccm
If robustness is more important than performance, then I prefer HMAC+encryption in a encrypt-then-MAC scheme over GCM and the like.
Jun
15
 reviewed Approve suggested edit on How do I decrypt ciphertext with this cipher?
Jun
15
 comment Can cryptography be used to hide routing information from the router?
It's not obvious to me that homomorphic encryption helps here
Jun
14
 reviewed Approve suggested edit on Why is H(message||secret_key) not vulnerable to length-extension attack?
Jun
14
 revised Why is H(message||secret_key) not vulnerable to length-extension attack?
added 64 characters in body
Jun
14
 reviewed Approve suggested edit on understanding a length extension attack
Jun
14
 answered Why is H(message||secret_key) not vulnerable to length-extension attack?
Jun
14
 comment Why is H(message||secret_key) not vulnerable to length-extension attack?
You can perform a length extension, but then the message doesn't end with the secret key anymore and is thus not a valid authentication tag.
Jun
14
 comment Would this simple encrypted chat program be feasible using One Time Pads?
@zuallauz D.W.'s point is valid. Security is only as strong as the weakest part. The strength of symmetric encryption(which your scheme tries to improve) is not the weakest part. It's also easy to increase the strength of symmetric crypto taking a minor performance hit, for example by cranking up the number of rounds or by using double encryption. The real problems are keeping the endpoints secure vs. malware, backdoors and physical access etc. and the key management i.e. how to securely get your partners (public) key)
Jun
13
 revised Scrypt as a KDF with one-time high-entropy input
edited tags
Jun
13
 revised KDF with low-entropy salts
edited tags
Jun
13
 revised Reason(s) for using a KDF for encryption keys
edited tags
Jun
13
 revised brute force attack on KDF vs KEY
edited tags
Jun
13
 revised What information to include is the 'info' input for HKDF?
edited tags
1 2 3 4 5 … 60