Generating RSA pairs

Peter M. Brigham pmbrig at
Sun May 5 09:23:09 EDT 2013

On May 2, 2013, at 7:08 PM, Igor de Oliveira Couto wrote:

> There are a few well-documented ways to gather usable, unique seeds, such as:
> * getting the user to type for 10-20 seconds, randomly picking chars entered (PGP used this technique when initially generating the keys for the user)
> * getting the user to move the cursor on the screen and randomly recording mouse coordinates
> * parsing time-based readings - ie., getting 'the millisecons', then combining it with 'the internet time', then picking a few of the characters randomly from the resulting string
> * asking the user to select 2 or 3 files in their system, and reading random bits from the files

Just wading through my email, so the conversation has already moved on, but for anyone interested, here's a somewhat "more random" random number generator:

function rRandom n
   -- returns a (more random) random number between 1 and n
   -- works for n up to ~ 4.29 billion
   put the long seconds into ss
   -- returns 6 digits after the decimal, ie, down to microseconds
   -- use the fractional part only:
   if "." is not in ss then
      -- very unlikely to hit it exactly on the full second, but just to be sure
      put 0 into ss
      delete char 1 to offset(".",ss) of ss -- 6 digits, maybe less
   end if
   set the randomseed to ss + random(1000000) + 1000
   return (random(4294967295) mod n) + 1
   -- 4294967295 (= 2^32 - 1) is the largest argument permissible for random()
end rRandom

-- Peter

Peter M. Brigham
pmbrig at

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