CodesInChaos

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	6,165 reputation	bio	website	github.com/CodesInChaos	visits	member for	1 year, 11 months
1927 badges		location	Munich, Germany		seen	9 hours ago

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Apr 14	comment	Comprehension question on a signature protocol based on the RSA assumption How about linking the paper?
Apr 13	comment	Is there an existing AEAD scheme with minimal IV requirements? You can in principle describe AES-CBC with encrypted IV + an IV-less MAC (CBC-MAC or HMAC) as an AEAD. I think it'd fulfill your requirements.
Apr 12	comment	Pseudo Random Generator (PRG) from Rabin function Looks like I'll need to look up the details of how to compute the order again. I thought $x^{\lambda(n)}=x \pmod n$ holds.
Apr 12	comment	Pseudo Random Generator (PRG) from Rabin function A better choice of modulus. The product of two large primes (say 512 bits each) should do the job.
Apr 12	comment	Pseudo Random Generator (PRG) from Rabin function Your immediate problem is the unfortunate choice of the modulus.
Apr 12	comment	Pseudo Random Generator (PRG) from Rabin function Might not cause your immediate problem, but should use a `BigInteger` class instead of `Math.Pow` and `double`.
Apr 8	comment	May the problem with DES using OFB mode be generalized for all feistel ciphers Your argument only works if reversing the subkeys has no effect.
Apr 7	comment	How secure is this perl script to use an AES encryption on files? At a glance I see two issues: 1) The key derivation is cheap. Use a proper salted password hash such as PBKDF2 or scrypt. 2) There is no MAC, this enables active attacks where an attacker modifies the ciphertext. These attacks are surprisingly strong. For example padding oracles can be used to convince the legitimate decrypter to leak enough information to leak the plaintext. That might not work with file encryption, but I strongly recommend using MACs.
Apr 7	comment	How fast can a wrong decryption key be detected using ECC? Typically ECC is not used for encryption at all. It's only used to determine a symmetric key that's used with a symmetric cipher to do the actual encryption. Your question depends on the choice of the symmetric encryption scheme and on the nature of the plaintext.
Apr 6	comment	Does a trace of SSL packets provide a proof of data authenticity? @SmitJohnth Non handshake data is authenticated with a MAC, so it's symmetric and can't be used to prove who authored that data to a third party.
Mar 27	comment	How to choose between AES-CCM and AES-GCM for storage volume encryption GCM might be a bit faster(depends on CPU), but I don't like it. It feels very fragile.
Mar 26	comment	AES ENCRYPTION ALGORITHM Why are you asking the same question twice?
Mar 26	comment	which asymmetric cipher provide highest performance? @rsa RSA is fast for encryption but really slow for decryption. You're comparing different security levels and you're not looking at a good ECC implementation.
Mar 23	comment	Can SRP be used with Elliptic Curves? It's certainly possible to use a protocol that generates a private key from a password hash with ECC. But the proof that the client possesses the key will be different.
Mar 21	comment	RSA Certificate Owner and Issuer line meanings? Look for X500 and X.509
Mar 20	comment	Security of Deterministic Encryption Scheme Pretty much the only inherent issue with deterministic encryption is that it leaks if two inputs are identical. So if you apply it to individual words, security will suck. If you apply it to complete and complex files, you'll probably be OK.
Mar 20	comment	Sensible usecase for restricting special characters in passwords? Some keyboards lack some characters, and outside ASCII you'll need to be careful about encoding.
Mar 20	comment	Even passwords are vulnerable to hash collision attacks? The adversary can inject material (though the salt might block any collision attack). But such a collision attack at best(from his point of view) allows the attacker to create an account for which he knows two different passwords. Not very useful...
Mar 20	comment	How does the rand() function in C work? Even when eyeballing the plot of `rand()` it often exhibits total failure
Mar 20	comment	How does the rand() function in C work? Given the typical implementation of `rand()`, you're using a quite generous definition of "works". IMO it does not work, even for non security related stuff.