Python3でrot13

Python3系でROT13する関数

import codecs
def rot13(str):
    print(codecs.encode(str, "rot-13"))

ksnctfのEasy Cipherの↓をいれてみる

EBG KVVV vf n fvzcyr yrggre fhofgvghgvba pvcure gung ercynprf n yrggre jvgu gur yrggre KVVV yrggref nsgre vg va gur nycunorg. EBG KVVV vf na rknzcyr bs gur Pnrfne pvcure, qrirybcrq va napvrag Ebzr. Synt vf SYNTFjmtkOWFNZdjkkNH. Vafreg >na haqrefpber vzzrqvngryl nsgre SYNT.

rot13("EBG KVVV vf n fvzcyr yrggre fhofgvghgvba pvcure gung ercynprf n yrggre jvgu gur yrggre KVVV yrggref nsgre vg va gur nycunorg. EBG KVVV vf na rknzcyr bs gur Pnrfne pvcure, qrirybcrq va napvrag Ebzr. Synt vf SYNTFjmtkOWFNZdjkkNH. Vafreg na haqrefpber vzzrqvngryl nsgre SYNT.")

ROT XIII is a simple letter substitution cipher that replaces a letter with the letter XIII letters after it in the alphabet. ROT XIII is an example of the Caesar cipher, developed in ancient Rome. Flag is ～(略)～

参考
How to ROT13 encode in Python3?
https://stackoverflow.com/questions/10576347/how-to-rot13-encode-in-python3