def avrrandom(self, n, seed=1):
'''avr-libc PRNG
According to http://arduino.cc/en/Reference/Long a long on
arduino (and therefore avr) is 4 bytes. Produces n//(8*4) bytes (~n
bits) from the avr-libc prng
NOTE: not very pythonic'''
for i in range(n // (8 * 4)):
# let b be 4 bytes from the prng
b = format(avrlibcrandom.random(), '032b')
yield ''.join(b)
def avrrandom(self, n, seed=1):
'''avr-libc PRNG
According to http://arduino.cc/en/Reference/Long a long on
arduino (and therefore avr) is 4 bytes. Produces n//(8*4) bytes (~n
bits) from the avr-libc prng
NOTE: not very pythonic'''
for i in range(n//(8*4)):
# let b be 4 bytes from the prng
b = format(avrlibcrandom.random(), '032b')
yield ''.join(b)
def fromcomplete(self, sequence):
'''Find the seed when given the whole sequence.'''
# Let's use lits
#lastk = [deque()]*1024
lastk = [[]]*1024
k = len(sequence)
while len(self.p) > 0:
i = self.p.pop()
srandom(i)
for x in xrange(k):
r = random()
if r == sequence[x]:
lastk[i].append(r)
else:
# We got the wrong value, pointless to go on
break
if lastk[i] == sequence:
return i
# Happens if the seed is larger than 2**10-1 or we have a bad sequence.
return None
def fromcomplete(self, sequence):
'''Find the seed when given the whole sequence.'''
# Let's use lits
#lastk = [deque()]*1024
lastk = [[]] * 1024
k = len(sequence)
while len(self.p) > 0:
i = self.p.pop()
srandom(i)
for x in xrange(k):
r = random()
if r == sequence[x]:
lastk[i].append(r)
else:
# We got the wrong value, pointless to go on
break
if lastk[i] == sequence:
return i
# Happens if the seed is larger than 2**10-1 or we have a bad sequence.
return None
def findseed(self, sequence, m=1):
'''Finds the seed given a sequcence that does not have to be
complete from the seed.
Let S_0 be the initial sequence of length k with s as seed,
and S_n be the sequence with radom variables
s_{n-k},..,s_k. Let S_1 be the observerd sequnce, also of
length k.
In each iteration, this program will generate all sequences
S_i of s_{last},...,s{last+k+m}.
Thus m is in a wayan estimation of C. One of those
performance-tuning thingies.
The program makes infinitely many iterations until it finds it
unless the debug value is set. '''
# Giveup option for testing purposes
giveup = 50
k = len(sequence)
lastk = [deque([]) for i in self.p]
# Expand all the deques by k elements from p[i] for each i.
# => generate initial sequences.
# 1024*k operations → O(k)
for i in self.p:
srandom(i)
#lastk[i] = deque([random() for _ in range(k)])
for _ in xrange(k):
lastk[i].append(random())
# If we recieved a sequence dervied directly from the seed
if list(lastk[i]) == sequence:
return i
#while True:
for _ in xrange(giveup):
# This has to be a little more sophisticated than a crude
# bruteforce attack.
#
# This program has the rather curious property that it has
# an essentially unknown running boundary. It is
# completely dependent upon the number of calls made to
# the PRNG before the sequence given to us appeared (until
# we find the sequence, we stay inside the while loop. Let
# C denote this value. Let m be our best estimation of C.
#
# For every value i, we have started with the intial sequnce
# of length k. In each iteration we will check east of the
# m+k sequential ques for a match.
for i in self.p:
for _ in range(m+k):
srandom(lastk[i][-1])
v = random()
lastk[i].popleft()
lastk[i].append(v)
if list(lastk[i]) == sequence:
return i
# If we haven't found anything yet, we stay in the while loop. This program
# may never halt, if we are given a bad sequence (that originated from some
# other PRNG or perhaps not from a PRNG at all).
# Giving up
return -1
#coding: utf-8
from stattests import StatTests, FipsTests
from seedfind import Seedfinder
from avrlibcrandom import random, srandom
f = open('samples.txt').read().split('\n')
seed = int(f[0])
seed = 526
srandom(seed)
seq = [random() for _ in range(1000)][990:]
print "Ég sendi inn þessa runu", seq
s = Seedfinder()
print "Ég fann", s.findseed(seq, 0), "en þú gafst mér", seed
def findseed(self, sequence, m=1):
'''Finds the seed given a sequcence that does not have to be
complete from the seed.
Let S_0 be the initial sequence of length k with s as seed,
and S_n be the sequence with radom variables
s_{n-k},..,s_k. Let S_1 be the observerd sequnce, also of
length k.
In each iteration, this program will generate all sequences
S_i of s_{last},...,s{last+k+m}.
Thus m is in a wayan estimation of C. One of those
performance-tuning thingies.
The program makes infinitely many iterations until it finds it
unless the debug value is set. '''
# Giveup option for testing purposes
giveup = 50
k = len(sequence)
lastk = [deque([]) for i in self.p]
# Expand all the deques by k elements from p[i] for each i.
# => generate initial sequences.
# 1024*k operations → O(k)
for i in self.p:
srandom(i)
#lastk[i] = deque([random() for _ in range(k)])
for _ in xrange(k):
lastk[i].append(random())
# If we recieved a sequence dervied directly from the seed
if list(lastk[i]) == sequence:
return i
#while True:
for _ in xrange(giveup):
# This has to be a little more sophisticated than a crude
# bruteforce attack.
#
# This program has the rather curious property that it has
# an essentially unknown running boundary. It is
# completely dependent upon the number of calls made to
# the PRNG before the sequence given to us appeared (until
# we find the sequence, we stay inside the while loop. Let
# C denote this value. Let m be our best estimation of C.
#
# For every value i, we have started with the intial sequnce
# of length k. In each iteration we will check east of the
# m+k sequential ques for a match.
for i in self.p:
for _ in range(m + k):
srandom(lastk[i][-1])
v = random()
lastk[i].popleft()
lastk[i].append(v)
if list(lastk[i]) == sequence:
return i
# If we haven't found anything yet, we stay in the while loop. This program
# may never halt, if we are given a bad sequence (that originated from some
# other PRNG or perhaps not from a PRNG at all).
# Giving up
return -1
#coding: utf-8
from stattests import StatTests, FipsTests
from seedfind import Seedfinder
from avrlibcrandom import random, srandom
f = open('samples.txt').read().split('\n')
seed = int(f[0])
seed = 526
srandom(seed)
seq = [random() for _ in range(1000)][990:]
print "Ég sendi inn þessa runu", seq
s = Seedfinder()
print "Ég fann", s.findseed(seq, 0), "en þú gafst mér", seed
