[SWPUCTF 2021 新生赛]crypto4

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已于 2024-04-21 16:56:47 修改

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分类专栏：密码学-RSA系列文章标签： python 网络安全密码学

于 2024-04-19 13:55:34 首次发布

本文链接：https://blog.youkuaiyun.com/2301_80216972/article/details/137961999

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文章讲述了如何使用gmpy2库在给定加密后的flag和大数n的情况下，通过分解n并计算欧拉函数来求出RSA的私钥d，进而解密旗标。

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下载看到附件：

from gmpy2 import *
from Crypto.Util.number import *

flag  = '**********'

p = getPrime(512)
q = next_prime(p)
m1 = bytes_to_long(bytes(flag.encode()))

e = 0x10001
n = p*q

flag1 = pow(m1,e,n)
print('flag= '+str(flag1))
print('n= '+str(n))

flag= 10227915341268619536932290456122384969242151167487654201363877568935534996454863939953106193665663567559506242151019201314446286458150141991211233219320700112533775367958964780047682920839507351492644735811096995884754664899221842470772096509258104067131614630939533042322095150722344048082688772981180270243
n= 521470172982603571803291017768640951348068480206635580641416482003660793319621324119679176978778752771030457559720060840785594537772914030875750613826748725733364318765001282471338619577301544184616805064036801897553997528825584383931071518157942952723589553009147525233774171925047027984507874304033870