hackaflag-crypto100.py

#!/usr/bin/python
# Hackaflag 2017 Etapa NATAL Crypto100 [Write-Up] 
# Jonatas Fil - Dark00x1n [RATF]
# RSA-768
# https://en.wikipedia.org/wiki/RSA_Factoring_Challenge
# https://en.wikipedia.org/wiki/RSA_numbers#RSA-768

import gmpy

# Modulo
N = 1062298437646102178982125849777616556940568446813929092985586137589152470725381990531187697078820602673983926292915001934764080223025406544777312096563547373014612492919701398580259368151634974370089837459356819607567494260480572449
# Expoente
e = 65537
# mensagem cifrada
c = 121560831698874219453267613174219141247779625979263684086055365282206190849386529369540754333346196170380400323865047328204751135058776179967797282368990382515924294891518016686180279409054094397243792496242298466435824664626111902
# p compativel
p = 33478071698956898786044169848212690817704794983713768568912431388982883793878002287614711652531743087737814467999489
q = N/p

inverte = gmpy.invert(e, (p-1)*(q-1))
print "\nDecipher value: " + str(inverte)

d = inverte

flag = pow(c,d,N)
print "\nFlag in decimal: " + str(flag)

FLAG = format(602873438782344394527399921786992769594048657669223244253021239583680398258312466721767404089469, 'x') # in hexadecimal
print "\nFlag in Hexadecimal: " + str(FLAG)

final = str(FLAG).decode("hex")

print "\nFlag: " + str(final)

# FLAG = HACKAFLAG{S0lv3d RSA-768, G1MM3 $50.000}