This website is outdated. It's updated version is available at www.cryptool.org/en/cto. Not all applications have been updated yet. Therefore, you can still use them here.

# CrypTool-Online

CrypTool-Online (CTO for short) offers applications for testing, learning and discovering old and modern cryptography.

### Highlights 7

AES Animation

Interactive animation of the AES algorithm

Corona Tracing

Demonstration of the cryptographic protocol DP-3T

Msieve Factorizer

Factorization of large numbers using a quadratic sieve

OpenSSL

Ported to the web browser with WebAssembly

Password Check

Another local password evaluation algorithm

Password Generator

Local generation of random passwords

Password Meter

Evaluates the strength of an entered password locally

### Ciphers 26

ADFG(V)X

Cipher from WW1, which substitutes and transposes

AES (step-by-step)

The most common modern encryption method

Atbash

Simple monoalphabetic substitution cipher originally used on the Hebrew alphabet

Autokey

Variant of Vigenère, which also uses plaintext as key

Beaufort

Vigenère cipher, which uses reversed alphabet

Bit Shift

Shifts the characters of a text bit by bit

Caesar / Rot13

Shifting cipher, which was used by Julius Caesar

Enigma (step-by-step)

World War 2 rotor encryption machine

Gronsfeld

Variant of Vigenère using a number as its key

Hill

Polygraphic substitution, based on linear algebra

Kamasutra

Substitution cipher described in the Kama Sutra (400 BC)

Monoalphabetic Substitution

Cipher that replaces letters with letters/characters

Multiplicative

Simplified variant of the affine cipher

Porta

Vigenère cipher with half the key space

RSA (step-by-step)

The most widespread asymmetric method for encryption and signing

RSA visual and more

Didactic preparation of RSA

Rail fence

Transposition cipher that uses a railfence pattern

Redefence

Railfence cipher that reads lines in any order

Rotation

Cipher writes plaintext in blocks and rotates them

SHA256

Secure Hashing Algorithm - SHA256

Scytale

Cipher that writes messages on a belt

Simple Column Transposition

Cipher that interchanges lines of the plaintext

Trithemius

Precursor of the Vigenère tableau (with fixed key)

Vernam

Using XOR for implementing a one-time pad (OTP)

Vigenère

First strong polyalphabetic cipher

XOR

Single bits are XORed (typical component of more complex ciphers)

### Codings 6

ASCII

Letters are replaced by numbers of the ASCII code

Bacon

Coding that encrypts and hides letters in sentences

Barcode

Characters are encoded by strokes of different thicknesses

Base64

Coding, which is based on a 64 number system

Huffman

Encodes characters with minimal long binary words

Morse Code

Encodes letters using dashes and dots

### Cryptanalysis 7

Autocorrelation

Correlates text with shifted versions of itself

Distributed AES Analysis

Demo attacking AES with distributed computing

Graphical Frequency Analysis

N-gram analysis that works interactively and graphically

Neural Cipher Identifier

Identifies the cipher type, with only a short given ciphertext

Number Converter

Converts numbers to various other number systems

Tabular N-gram Analysis

Counts and visualizes the number of n-grams

Vigenère Analysis

Determines the length of the key of a Vigenère cipher

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