def comb_attack(self):
# dis generator
solver_name = 'btor'
solver_obf = Solver(name=solver_name)
solver_key = Solver(name=solver_name)
solver_oracle = Solver(name=solver_name)
attack_formulas = FormulaGenerator(self.oracle_cir, self.obf_cir)
f = attack_formulas.dip_gen_ckt
# f = simplify(f)
solver_obf.add_assertion(f)
f = attack_formulas.key_inequality_ckt
# f = simplify(f)
solver_obf.add_assertion(f)
iteration = 0
while 1:
# query dip generator
if solver_obf.solve():
dip_formula = []
dip_boolean = []
for l in self.obf_cir.input_wires:
t = Symbol(l)
if solver_obf.get_py_value(t):
dip_formula.append(t)
dip_boolean.append(TRUE())
else:
dip_formula.append(Not(t))
dip_boolean.append(FALSE())
logging.info(dip_formula)
# query oracle
dip_out = []
for l in self.oracle_cir.output_wires:
t = self.oracle_cir.wire_objs[l].formula
solver_oracle.reset_assertions()
solver_oracle.add_assertion(t)
if solver_oracle.solve(dip_formula):
dip_out.append(TRUE())
else:
dip_out.append(FALSE())
logging.info(dip_out)
# add dip checker
f = []
for i in range(len(attack_formulas.dip_chk1)):
f.append(And(Iff(dip_out[i], attack_formulas.dip_chk1[i]),
Iff(dip_out[i], attack_formulas.dip_chk2[i])))
f = And(f)
subs = {}
for i in range(len(self.obf_cir.input_wires)):
subs[Symbol(self.obf_cir.input_wires[i])] = dip_boolean[i]
# f = simplify(f)
f = substitute(f, subs)
solver_obf.add_assertion(f)
solver_key.add_assertion(f)
iteration += 1
logging.warning('iteration: {}'.format(iteration))
else:
logging.warning('print keys')
if solver_key.solve():
key = ''
for i in range(len(self.obf_cir.key_wires)):
k = 'keyinput{}_0'.format(i)
if solver_key.get_py_value(Symbol(k)):
key += '1'
else:
key += '0'
print("key=%s" % key)
else:
logging.critical('key solver returned UNSAT')
return
def comb_attack(self):
# dis generator
solver_name = 'yices'
solver_obf = Solver(name=solver_name)
solver_key = Solver(name=solver_name)
self.solver_oracle = Solver(name=solver_name)
attack_formulas = FormulaGenerator(self.oracle_cir, self.obf_cir)
f = attack_formulas.dip_gen_ckt
# f = simplify(f)
solver_obf.add_assertion(f)
f = attack_formulas.key_inequality_ckt
# f = simplify(f)
solver_obf.add_assertion(f)
for l in self.oracle_cir.wire_objs:
self.solver_oracle.add_assertion(l.formula)
dip_list = []
stateful_keys = []
iteration = 0
while 1:
# query dip generator
if solver_obf.solve():
dip_formula = []
dip_boolean = []
for l in self.oracle_cir.input_wires:
s = Symbol(l.name)
if solver_obf.get_py_value(s):
dip_formula.append(s)
dip_boolean.append(TRUE())
else:
dip_formula.append(Not(s))
dip_boolean.append(FALSE())
logging.info(dip_formula)
# query oracle
dip_out = self.query_oracle(dip_formula)
logging.info(dip_out)
# check for stateful condition
if dip_formula in dip_list:
# ban stateful key
logging.info("found a repeated dip!")
# check outputs for both keys
key = None
for l in self.obf_cir.output_wires:
s1 = Symbol(l.name + '@dc1')
s2 = Symbol(l.name + '@dc2')
if solver_obf.get_py_value(
s1) != solver_obf.get_py_value(s2):
if solver_obf.get_py_value(
s1) != self.solver_oracle.get_py_value(
Symbol(l.name)):
key = '0'
else:
key = '1'
break
if key == None:
logging.critical(
'something is wrong when banning keys')
# find assigned keys
key_list = []
for l in self.obf_cir.key_wires:
k = Symbol(l.name + '_' + key)
if solver_obf.get_py_value(k):
key_list.append(k)
else:
key_list.append(Not(k))
stateful_keys.append(key_list)
# ban the stateful key
f = Not(And(key_list))
solver_obf.add_assertion(f)
solver_key.add_assertion(f)
if len(stateful_keys) % 5000 == 0:
logging.warning('current stateful keys: {}'.format(
len(stateful_keys)))
continue
else:
dip_list.append(dip_formula)
# add dip checker
f = []
f.append(
attack_formulas.gen_dip_chk(iteration * 2, '_0',
dip_boolean))
f.append(
attack_formulas.gen_dip_chk(iteration * 2 + 1, '_1',
dip_boolean))
for i in range(len(self.obf_cir.output_wires)):
l = self.obf_cir.output_wires[i].name
f.append(
And(
Iff(dip_out[i],
Symbol(l + '@{}'.format(iteration * 2))),
Iff(dip_out[i],
Symbol(l + '@{}'.format(iteration * 2 + 1)))))
f = And(f)
solver_obf.add_assertion(f)
solver_key.add_assertion(f)
iteration += 1
logging.warning('iteration: {}'.format(iteration))
else:
logging.warning('print keys')
logging.warning('stateful keys: {}'.format(len(stateful_keys)))
if solver_key.solve():
key = ''
for l in self.obf_cir.key_wires:
if solver_key.get_py_value(Symbol(l.name + '_0')):
key += '1'
else:
key += '0'
print("key=%s" % key)
else:
logging.critical('key solver returned UNSAT')
return
