From: Shannon Fang <xrfang@...>
Date: 2006-04-18T03:03:55+09:00
Subject: a simple RSA

Hi All,

I tried to implement a simple RSA crypto for my work. It seems all works 
fine, except that I am not satisfied with the code I wrote below:

def str_to_num(s)
  h = '0x'
  (0...s.length).each do |i|
    h += "%02x" % s[i]
  end
  eval(h)
end

def num_to_str(n)
  s = ''
  while n > 0 do
    s = "%c" % (n & 0xFF) + s
    n = n >> 8
  end
  s
end

These 2 functions convert string to bignum and vise-versa. It works, but I 
feel there should be better (faster) way to do this.

Could anyone point the way out?

Thanks!
Shannon