From charlesreid1

Problem Statement

This question is about a method of encrypting ASCII text.

Each character in ASCII has some representation (e.g., A=65, *=42, k=107)

Encryption technique is to take text file, convert bytes to ASCII, and XOR each byte with a character from a secret key

Password method: use a password in place of a secret one-time pad; shorter than message, so repeated cyclically throughout method.

You are given a file with encrypted ascii codes, knowledge that plain text must contain common English words, and told encryption key consists of 3 lowercase characters. Decrypt message, find sum of ascii values in original text.

Sample file looks like this: 36,22,80,0,0,4,23,...

Link: https://projecteuler.net/problem=59

Approach

Flags