baigeiRSA
baigeiRSA
打开附件有两个：
1.
import libnum
from Crypto.Util import number
from secret import flag
size = 128
e = 65537
p = number.getPrime(size)
q = number.getPrime(size)
n = p*q
m = libnum.s2n(flag)
c = pow(m, e, n)
print('n = %d' % n)
print('c = %d' % c)
2.
n = 88503001447845031603457048661635807319447136634748350130947825183012205093541
c = 40876621398366534035989065383910105526025410999058860023908252093679681817257这n、c、e、p、q合起来一看就知道是RSA算法
已知n=p*q，所以使用yafu工具分解出p、q值。
语句：.\yafu-x64.exe “factor(n)”
脚本
import gmpy2
import libnum
q = 274539690398523616505159415195049044439
p = 322368694010594584041053487661458382819
n = 88503001447845031603457048661635807319447136634748350130947825183012205093541
c = 40876621398366534035989065383910105526025410999058860023908252093679681817257
e = 65537
phi = (q-1)*(p-1) #phi为n的欧拉函数
d = int(gmpy2.invert(e,phi)) #d是私钥
flag = pow(c,d,n)
print(libnum.n2s(flag))
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#b'HSCTF{@Zh3n_Ba1_G3i!@}'