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May
31
comment How to test if a number is a primitive root?
I mistyped. It was p.
May
31
comment How to test if a number is a primitive root?
The output is: <code>PRIME FACTOR x1 PRIME FACTOR x2</code>, so it should check for primarity. And there are only 2 factors.
May
31
comment How to test if a number is a primitive root?
I'll write down what I've done and you'll say if I'm right. I tested if the modulus is prime with rabin-miller test, the program is here en.literateprograms.org/Miller-Rabin_primality_test_(Python). It was prime, so I used this ftp.computing.dcu.ie/pub/crypto/factor.exe program to factor the modulus-1 since phi(prime) = prime - 1. It printed out 2 and another prime. So then I calculated g ^ q % (p-1) for all factors where q is the factor and they were != 1. So g should be a generator, right?
May
31
comment Crack SHA1 hash code
@user236501 I think you misunderstood that. You can't change data before unknown values and get a correct hash.
May
31
comment Reversing SHA1 (don't know the correct term)
Would you probably write a short summary of your post? It's hard to read.
May
31
comment Reversing SHA1 (don't know the correct term)
Afaik output of compression function = output of hash function, since opposing to MD5 SHA-1 doesn't have finalisation.
May
30
comment How to test if a number is a primitive root?
Ok, I tested and that number is a safe prime, i.e. p=2q+1, p and q are prime. How to test now whether a number is a primitive root?
May
30
comment How to test if a number is a primitive root?
Assume at least 256 bits. Is there no ready software? What if p-1 is prime too? Do you know a software to test if a number is prime?
May
30
comment How to test if a number is a primitive root?
Well, I haven't really understood your answer. Could you give me an algorith to prove it or probably a program source?
May
30
comment understanding a length extension attack
It's really lot of text, hard to understand. Would help if you explain yourself more shortly.
May
30
comment Reversing SHA1 (don't know the correct term)
Yes, you are right - 16 ints / 64 bytes. 20 bytes is hash length. <br> I think it will work - if you have current block data, you can generate expanded buffer and then reverse the hash generation to beginning of the block.
May
30
comment Reversing SHA1 (don't know the correct term)
@Reid no, it's not, but what would it change?
May
30
comment Reversing SHA1 (don't know the correct term)
pad(X) means it has length of 1 block (20 bytes in case of SHA1). "This sounds like a homework question." - even if, is that bad?
May
30
comment What are the requirements of a nonce?
I'm confused: does it mean "nonce actually don't have to be random, but sometimes yes"?
May
30
comment What are the requirements of a nonce?
Is there a real source for that? Our professor has given it as a random number on his lection.
May
30
comment What are the requirements of a nonce?
So defining it as a random number is wrong? Wikipedia is not a source.
May
24
comment Why is SRP not widely used?
@PaĆ­loEbermann The difference between SRP and SSL is not that much if you have a centralised organisation and can get SSL certificates or a CA for your servers. You'll surely have a centralised directory which you have to authenticate regardless of the resource you are accessing. If you don't want web resources to steal your password you can use OAuth or something so you have to input your password on only one secure site. The advantage of SRP - you don't have to trust the server you authenticate on - doesn't have to much value in good built centralised environment. IMHO.
May
24
comment Can I use a key-derivation-function as the hash function H in SRP?
Wikipedia is not a source.
May
24
comment Why is SRP not widely used?
@PaĆ­loEbermann I think your post doesn't belong here :)
May
22
comment Is a second preimage attack on MD5 feasible?
AFAIR there are even no practical attacks for MD4.