# Samer Meggaly

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bio website sites.google.com/site/… location Alexandria, Egypt age 24 member for 3 years seen Jan 27 at 6:22 profile views 31

I am a Senior year student at Computer and Systems Engineering Department,

Faculty of Engineering,

Alexandria University, Egypt.

# 19 Actions

 Jan25 awarded Good Question Oct18 awarded Famous Question Jul2 awarded Nice Question Nov19 awarded Notable Question Sep1 awarded Popular Question Aug11 awarded Autobiographer Apr25 awarded Supporter Apr7 comment Predicting PRNG given some of its previous output I know that the range for (2x + 5) mod p is [0..p-1], but wouldn't that make x < (p-5)/2 that is (2^56-5)/2 ? and the maximum value for p will be (2^56-1), please correct me if i am getting anything wrong. Apr7 comment Predicting PRNG given some of its previous output No, this is a mistake of mine, x and y and chosen randomly in [0..p-1] and the problem stated that p is 56-bits. Apr6 comment Predicting PRNG given some of its previous output Thanks, for the correction. Apr6 comment Predicting PRNG given some of its previous output Thanks @fgrieu, i have two points that i tried to figure out, but i couldn't. First, how did u limit the range of p to [2^55, 2^56] ... Second, also the same for Xj and Yj. Apr6 comment Predicting PRNG given some of its previous output First, thanks a lot for the help. Second, i still have some points that i cant understand ... how did u determine the ranges for Kx and Ky ? ... Also, i don know whether i got the second step or not, so u mean that for all values of X [0, 2^56] and for all values of bit-0 of p {0, 1}, find 3 pairs of (Kx, Ky) that will generate the 2nd, 3rd and 4th outputs. Apr6 asked Predicting PRNG given some of its previous output Apr1 awarded Scholar Apr1 accepted How does one attack a two-time pad (i.e. one time pad with key reuse)? Apr1 comment How does one attack a two-time pad (i.e. one time pad with key reuse)? Thanks, a lot i solved the problem. I started with ' the ' as you said and got 'robab' which i guessed would be 'probably'. I kept doing this with some guesses until i solved the whole message. Thanks again. Apr1 comment How does one attack a two-time pad (i.e. one time pad with key reuse)? Yes, your totally right. I was mistaken with that part, but it is my very first trial in cryptography. I got it now Apr1 awarded Student Mar31 asked How does one attack a two-time pad (i.e. one time pad with key reuse)?