# tadpole#### Crypto - 262 solves**# Description## tadpoles only know the alphabet up to b... how will they ever know what p is?	# Challenge```from Crypto.Util.number import bytes_to_long, isPrimefrom secrets import randbelow
p = bytes_to_long(open("flag.txt", "rb").read())assert isPrime(p)
a = randbelow(p)b = randbelow(p)
def f(s):    return (a * s + b) % p
print("a = ", a)print("b = ", b)print("f(31337) = ", f(31337))print("f(f(31337)) = ", f(f(31337)))**```
# Solution
### The following is my script for solving the problem, it is very simple and everyone will understand it at a glance!
```from Crypto.Util.number import *from secrets import randbelow
a = 7904681699700731398014734140051852539595806699214201704996640156917030632322659247608208994194840235514587046537148300460058962186080655943804500265088604049870276334033409850015651340974377752209566343260236095126079946537115705967909011471361527517536608234561184232228641232031445095605905800675590040729b = 16276123569406561065481657801212560821090379741833362117064628294630146690975007397274564762071994252430611109538448562330994891595998956302505598671868738461167036849263008183930906881997588494441620076078667417828837239330797541019054284027314592321358909551790371565447129285494856611848340083448507929914s =31337t = a * s + bk31337 = 52926479498929750044944450970022719277159248911867759992013481774911823190312079157541825423250020665153531167070545276398175787563829542933394906173782217836783565154742242903537987641141610732290449825336292689379131350316072955262065808081711030055841841406454441280215520187695501682433223390854051207100kff = 65547980822717919074991147621216627925232640728803041128894527143789172030203362875900831296779973655308791371486165705460914922484808659375299900737148358509883361622225046840011907835671004704947767016613458301891561318029714351016012481309583866288472491239769813776978841785764693181622804797533665463949
for i in range(1,100000000):    print("当前i值为：",i)    p = (t - k31337) // i    if isPrime(p) == 1:        if (a * k31337 + b) % p == kff:            print("p的值为：",p)            p_str = long_to_bytes(p)            print(p_str)            break```