c't Know-how 2024

The c't Know-how 2024 special issue offers in-depth knowledge on IT topics. It examines long-standing IT myths for their accuracy, such as whether changing passwords regularly actually enhances security.



The editorial team explains the workings of AI models and their potential beyond automated text and image generation.AI image generating tools sometimes deliver unexpected results and eavesdropping cars may enhance road safety in the future.



The special issue also provides answers to unexpected questions - such as how to decrypt a QR code, mathematical methods that may not have been taught by your math teacher, and how to crack an encryption that has challenged scientists for 300 years.



The c't magazine for computer technology is Europe's most subscribed computer title. For over 40 years, c't has been characterized by thematically diverse, expertly grounded and independent journalism. More than 80 experts regularly report on current developments in the IT sector and scrutinize the latest hardware and software in the c't test laboratory.



Online, c't offers computer professionals and demanding users a comprehensive collection of tips and tricks for PC usage, reading samples from magazine articles, extensive services, and information about the magazine (e.g., research in the magazine archive). This offering is rounded off with its own forum.



Demystifying IT Myths



Is it true that AI is as power-hungry as we often hear? And what about the rumor that every printer prints invisible codes? We examine widespread myths about sustainability in the IT world, operating systems, security, and hardware.



6 IT myths checked by c't magazine

10 myths about Windows and Linux

14 security myths illuminated

18 hardware myths from printers to WLAN



How AI Works



The thought patterns behind artificial intelligence or its ability to recognize emotions are probably known by few. Similarly, that image generators can be manipulated to confuse a dog with a cat.



24 Transformers: Language AI with focus

32 Explainable AI reveals its thought concepts

38 Manipulated images sabotage AIs

44 AI recognizes emotions



Exciting Research Developments



A curated mix from the colorful world of science: Listening cars and tiny artificial noses that sniff out gas molecules, as well as the James Webb Telescope, whose data you can even analyze yourself.



50 The car learns to listen for signals

56 Artificial nose detects gas molecules

62 Brainwaves control keyboard & prosthetics

68 The technology of the James Webb Telescope

76 Interactively analyzing data from the JWST



Nerd Knowledge Explained



Getting to the bottom of Rubik's cubes, crafting an AI rapper, or deciphering QR codes by hand – these are topics where expertise isn't necessary, but desired. Those interested in specialized knowledge on nerdy topics will find themselves at home here.



84 God's Number for the Rubik's cube

92 Quick calculations

100 Decoding QR codes by hand

108 Producing rap songs with the help of AI



Cracking Historical Encryptions



Although old encryptions play no role today, they still serve as good teaching examples to dive into the world of cryptography. Some were far ahead of their time and took hundreds of years to be deciphered.



114 Messages from the Vatican deciphered

120 Maximilian ciphers decrypted

126 Programming the Vigenère cipher in Python

132 Cracking the Vigenère cipher with the Kasiski test



About the Magazine



3 Editorial

91 Imprint

138 Preview: c't Windows projects