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Nov
11
accepted How can two (or more) parties share and agree upon a common random seed?
Nov
11
comment How can two (or more) parties share and agree upon a common random seed?
@nightcracker: I was thinking about generating large random numbers, as cutting them is trivial and they may be useful when the requirements change. And I was thinking about seeding Salsa20 where 256 bits fit perfectly (as the key).
Nov
10
asked How can two (or more) parties share and agree upon a common random seed?
Oct
18
awarded  Scholar
Oct
18
comment Encryption of small messages
I was actually interested in a length preserving encyption, but I failed to state it, and your answer is interesting, too. Thanks.
Oct
18
accepted Encryption of small messages
Oct
18
comment Encryption of small messages
@Thomas Pornin: I didn't say that I wanted a length preserving encryption, but you understood it well. Thanks for the perfect answer.
Oct
17
revised Encryption of small messages
added 560 characters in body
Oct
17
awarded  Student
Oct
17
asked Encryption of small messages
Apr
7
awarded  Nice Answer
Feb
14
comment How to best obtain bit sequences from throwing normal dice?
@Mok-Kong Shen: Yes, there's an efficiency drop for 3 rolls. You figures seem to be right.
Jan
31
awarded  Yearling
Jan
31
answered How to best obtain bit sequences from throwing normal dice?
Jan
17
comment LFSR for small numbers with large periods
@gl3829: No idea, what you're doing wrong, but fgrieu is obviously right. Try to pick the lower 1 bit. According to you you'll get a period of two, but it must be just like described in the second paragraph. Moreover, for any $m<n$ there's no number missing. I'd guess your LSFR is wrong.
Oct
28
comment How do ciphers change plaintext into numeric digits for computing?
@fgrieu: This is surely true (and I should have said it), but this goes far beyond "converting message into number" (which is probably what the OP wanted to know).
Oct
28
awarded  Editor
Oct
28
revised Is there an algorithm for factoring N, which is just as simple as this one, but faster?
Withdrawing the statement about trial division.
Oct
28
comment Is there an algorithm for factoring N, which is just as simple as this one, but faster?
@Thomas: Doesn't it? I'm basically saying that the choice of Ň gains nothing. So yes, there are better algorithms out there, and for number as small as the given one it's easy to implement.
Oct
28
comment Is there an algorithm for factoring N, which is just as simple as this one, but faster?
I'm no expert in cryptography and have spent only few minutes reading it, but it looks bad too. Unfortunately, whenever it looks like it needs no advanced math, it can't be right (unless it's one of the known algorithms). Note that something as simple as Pollard's rho can factor a number like the above in a few milliseconds.