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Apr
16
answered Is it possible to brute-force a hash algorithm of 32 bits
Apr
15
revised Time taken for a brute force attack on a key size of 64-bits
deleted 131 characters in body
Apr
15
answered Homomorphic Encryption or not
Apr
15
comment SHA1 collision for first 32 bits for two different message
That code is just completely wrong. You're not altering the message at all, and I don't see you comparing 32 bits either. First decompose your problem and generate multiple methods for each part. Test these separately. Then combine them to to create the code. For instance, the comparison of the 4 bytes can be separated out. So can the generation of the messages and - of course - the creation of the hash.
Apr
15
revised Time taken for a brute force attack on a key size of 64-bits
added the fact that each bit doubles the key space, thought it was important. Required uite a bit of shuffling though, highlighted some stuff
Apr
15
comment Can RSA-PSS signing be made deterministic without loss of security?
With regards to making this the standard way: you could still make this non-deterministic by including a salt, right? Not all protocols work equally well with deterministic signatures (I assume).
Apr
15
revised Time taken for a brute force attack on a key size of 64-bits
added 7 characters in body
Apr
15
revised Time taken for a brute force attack on a key size of 64-bits
added 554 characters in body
Apr
15
answered Time taken for a brute force attack on a key size of 64-bits
Apr
15
comment Can RSA-PSS signing be made deterministic without loss of security?
Beware that using any operation on the private key other than RSA will not be compatible with most hardware tokens. The encoding of the private key must be deterministic as well (possibly over multiple implementations) or your end result won't be deterministic either. Finally note that PKCS#1 v1.5 padding for signature generation isn't broken so PSS isn't really required to generate a signature that's most likely - but not provably - secure. Good question regardless.
Apr
14
comment What is the security strength of an n-bit HMAC?
Probably because the key is hashed twice, before and after the message (after XOR'ing the key with two different constant bit strings to create ipad & opad, to be precise). Not 100% on that, but it seems the most reasonable explanation.
Apr
14
comment What is necessary for generating an elliptic curve?
Bouncy Castle is able to generate curve domain parameters if I'm not mistaken. It takes pretty long, maybe somewhat less in Java 9 :)
Apr
14
comment How does Hash with random cryptography work?
Or possibly SRP of course, OK, the only way to protect a small plaintext password or password hash over such a password is TLS, that comment was slightly over the top...
Apr
14
answered Is ssl_sign safe as it is using OPENSSL_PKCS1_PADDING
Apr
14
comment Is Threefish the only cipher with 1024 bits of security?
Heh, I would not want to use an RSA key that provides 1024 bits of security. The size of the key would be gargantuan. (You know, I've always liked that word... 'gargantuan'... so rarely have an opportunity to use it in a sentence. :P ) Key size does not equal cryptographic strength.
Apr
14
comment Sending KCV (key check value) with cipher text
@fgrieu Yup, using it with enough care and/or for key derivation would work fine. If that's not required I either completely skip the identifier or I check it against a single value though.
Apr
14
revised How to reverse this hash function?
rolled back to a previous revision
Apr
14
comment How does Hash with random cryptography work?
The salt usually consist of random bits, not characters. 128 bits is plenty (i.e. 16 bytes or 32 hexadecimal characters, if you must). The example of the bank is flawed; a 6 character password could still be brute forced by Edvard, who knows the salt (as you correctly pointed out). The only way to secure the password login is TLS or possibly other devices (telephone or PIN card reader that generates a one-time-password).
Apr
14
comment Sending KCV (key check value) with cipher text
@fgrieu Thats very dangerous practice. Never trust your input. Before you know it you're using the wrong key (hi XML-enc vulnerability...).
Apr
13
answered Deriving Minimum Description Length of Substitution Key