اليوم بيكون عندنا رايت اب عن تحدي Leaks #AtHack
كان من تحديات الكربتو واصعبهم وواحد من اصعب التحديات في المسابقة
كان من تحديات الكربتو واصعبهم وواحد من اصعب التحديات في المسابقة
step 1 : Factor n using private key exposure attack
since we have 347 bits of private key d : the attack works because n is 1024bits and 347 > 1024/4 = 256
so now we facotred the n into p and q ,
github.com , this script will only work with sage shell
since we have 347 bits of private key d : the attack works because n is 1024bits and 347 > 1024/4 = 256
so now we facotred the n into p and q ,
github.com , this script will only work with sage shell
step 2 : get the first part of the flag:
we convert p into binary and take last 8 bits and convert them to int and xor them with the last item of cipher1
for the next iteration we need to calulate the modular square root.
we do that because p % 4 = 1 so we the modular square root
we convert p into binary and take last 8 bits and convert them to int and xor them with the last item of cipher1
for the next iteration we need to calulate the modular square root.
we do that because p % 4 = 1 so we the modular square root
step3 : get second part of flag
we do the same as part one but to calculate the modular square root we see that q % 8 = 1 so we use tonelli shanks algorithm.
link : rosettacode.org
we do the same as part one but to calculate the modular square root we see that q % 8 = 1 so we use tonelli shanks algorithm.
link : rosettacode.org
والشيء الجميل جدا انه بعد المسابقة تواصل معي اللي كان مسوي تحديات الكربتو يسالني عنها , هو نفس الشخص اللي جلدني في المسابقة 😂😂 لان التحدي كان اي واحد يحله لازم يشرح كيف حله
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