Cryptography Reference
In-Depth Information
Hash the chained entropy values.
if (Hashres != NULL)
{
ripeinit (&hws);
ripefinish (Hashres, &hws, Seedbytes, nextfree);
}
Seed as an integer in
CLINT
format.
if (Seed_l != NULL)
{
byte2clint_l (Seed_l, Seedbytes, nextfree);
}
Overwrite and deallocate seed.
SeedTime = 0;
local_memset (Seedbytes, 0, LenSeedbytes);
local_memset (&hws, 0, sizeof (hws));
free (Seedbytes);
return MissingEntropy;
}
For an extensive discussion and ideas for obtaining start values, see [Gut1],
[Gut2], [East], [Matt].
2
12.2.2 The BBS Random Number Generator
A random number generator that has been well researched with regard to its
cryptographic properties is the BBS bit generator of L. Blum, M. Blum, and M.
Shub, which is based on results of complexity theory. We would like now to
describe the process and then implement it, although without getting into the
theoretical details, for which see [Blum] or [HKW], Chapter IV and Section VI.5.
We require two prime numbers
p, q
congruent to
3
modulo
4
, which we
multiply together to obtain a modulus
n
, as well as a number
X
that is relatively
2
For highly sensitive applications, the generation of start values or even entire random se-
quences of
genuine
random numbers using suitable hardware components is always to be
preferred.
