28 lines
700 B
Factor
Executable File
28 lines
700 B
Factor
Executable File
USING: kernel math sequences namespaces
|
|
math.miller-rabin combinators.lib
|
|
math.functions accessors random ;
|
|
IN: random.blum-blum-shub
|
|
|
|
! Blum Blum Shub, n = pq, x_i+1 = x_i ^ 2 mod n
|
|
! return low bit of x+1
|
|
TUPLE: blum-blum-shub x n ;
|
|
|
|
<PRIVATE
|
|
|
|
: generate-bbs-primes ( numbits -- p q )
|
|
[ [ random-prime ] curry [ 4 mod 3 = ] generate ] dup bi ;
|
|
|
|
: next-bbs-bit ( bbs -- bit )
|
|
dup [ x>> 2 ] [ n>> ] bi ^mod [ >>x drop ] [ 1 bitand ] bi ;
|
|
|
|
PRIVATE>
|
|
|
|
: <blum-blum-shub> ( numbits -- blum-blum-shub )
|
|
generate-bbs-primes *
|
|
[ find-relative-prime ] keep
|
|
blum-blum-shub boa ;
|
|
|
|
M: blum-blum-shub random-32* ( bbs -- r )
|
|
0 32 rot
|
|
[ next-bbs-bit swap 1 shift bitor ] curry times ;
|