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Oct
1
comment Why is GCM only usable for ciphers with a 128-bit block size?
To make things worse, GHash's security doesn't scale down well to 64 bit MACs or smaller fields.
Oct
1
comment Why is GCM only usable for ciphers with a 128-bit block size?
@Melab It can be generalized, but there are many equally valid generalizations and the designers didn't bother to pick particular ones.
Oct
1
comment Is it possible to add error propagation to OTP?
What's the goal of this modification? Which security properties do you want to achieve? In modern crypto it's standard practice to use a MAC to reject any modified ciphertexts. There are even MACs secure against computationally unbounded adversaries, which pair ideally with the one-time-pad.
Oct
1
revised Is it possible to add error propagation to OTP?
edited tags
Oct
1
comment Is it possible to add error propagation to OTP?
You could encrypt the message with a conventional cipher (perhaps AES-SIV) or an unkeyed all-or-nothing transformation before encrypting with the one-time-pad.
Sep
30
revised Determine if a public key point y is negative or positive, odd or even?
added 159 characters in body
Sep
30
revised Determine if a public key point y is negative or positive, odd or even?
added 159 characters in body
Sep
30
answered Determine if a public key point y is negative or positive, odd or even?
Sep
30
comment Which ECB ciphertext stealing scheme is this?
Perhaps something CFB or OFB like.
Sep
30
comment Ciphertext and tag size and IV transmission with AES in GCM mode
If you want to use short MACs use a different MAC algorithm (e.g. HMAC).
Sep
30
comment Is truncating a SHA512 hash to the first 160 bits as secure as using SHA1?
@Ángel In general that shouldn't be true. But CRC32 has a special structure so depending on how you created those inputs it might have had far fewer collisions than an ideal hash. For example CRC32 doesn't have any collisions if you hash 4 byte messages, some people don't even consider it a hash.
Sep
30
comment Is it possbile to get same set of public and private keys twice while creating CSR ? If so where does the conflict happens !?
Using a correctly functioning CSPRNG to generate the keys, the chance of a collision are astronomically small. Pretty much the only way such a thing can happen is a bug, such as an insufficiently seeded PRNG, in which case you have bigger problems than just a collision.
Sep
29
reviewed No Action Needed Is SHA-256 secure as a CTR block cipher?
Sep
29
reviewed No Action Needed How does cryptanalysis of the Playfair cipher work?
Sep
29
reviewed No Action Needed With a true random number generator at hand, how to implement one-time pad?
Sep
29
reviewed No Action Needed Is differential calculus related to RSA?
Sep
29
reviewed No Action Needed Feldman's VSSS: Showing the Correctness of shares that are Consistent
Sep
29
reviewed No Action Needed Would it be secure to use random numbers from random.org in a cryptographic solution?
Sep
29
reviewed No Action Needed RSA with small exponents?
Sep
29
reviewed No Action Needed Does the elliptic curve (EC) cryptosystem outperform RSA and DL cryptosystems?