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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.
Oct
28
answered Is there an algorithm for factoring N, which is just as simple as this one, but faster?
Sep
10
answered Calculating the inverse modularity of the determinant for Hill cipher
Sep
4
awarded  Commentator
Aug
31
comment Can you help me with this Random Number Generator function?
Can't any even-permutations-only generating cipher be made "perfect" by a trivial postprocessing conditionally switching two outputs (with a 50% probability based on the key)?
Aug
30
comment No SHA-1 collision? Yet SHA-1 is broken?
@Andrew Tomazos - Fathomling: Using the "birthday paradox", there's a brute force attack against any hash of length 160 bits (like SHA-1) taking $2^{80}$ operations. Anything faster is a break.
Aug
30
comment Do I have to have a different salt for each password?
What I meant wasn't the UI, but using the whole string the way the OP proposed, i.e., something like searching for PBKDF2(username + ":" + password).
Aug
30
comment Do I have to have a different salt for each password?
What about the user entering a single string composed of their username and their password (possibly with a separator)? Doesn't this schema have exactly the same strength as the classical one?