Skip to main content
Settings
Search
Appearance
Theme Mode
About
Jekyll v3.10.0
Environment Production
Last Build
2026-05-22 22:41 UTC
Current Environment Production
Build Time May 22, 22:41
Jekyll v3.10.0
Build env (JEKYLL_ENV) production
Page Location
Page Info
Layout default
Collection docs
Path _docs/wargames/overthewire/krypton/krypton3.md
URL /docs/wargames/krypton/krypton3/
Date 2026-04-07
Theme Skin
SVG Backgrounds
Layer Opacity
0.6
0.04
0.08

Krypton3

By Amr

Level Info ---------- Well done. You've moved past an easy substitution cipher.

Estimated reading time: 0 minutes

Table of Contents

Source: This content is aggregated from overthewire (MIT). Visit the original repository for the latest version.

Level Info

Well done. You’ve moved past an easy substitution cipher.

The main weakness of a simple substitution cipher is repeated use of a simple key. In the previous exercise you were able to introduce arbitrary plaintext to expose the key. In this example, the cipher mechanism is not available to you, the attacker.

However, you have been lucky. You have intercepted more than one message. The password to the next level is found in the file ‘krypton4’. You have also found 3 other files. (found1, found2, found3)

You know the following important details:

  • The message plaintexts are in American English (*** very important) - They were produced from the same key (*** even better!)

Enjoy.