Which of the following steganography utilities is used to conceal messages in ASCII text by appending whitespace to the end of lines?

The chosen steganography utility that is used to conceal messages in ASCII text by appending whitespace to the end of lines is indeed SNOW. This utility specifically manipulates the whitespace characters, which are often overlooked in text files, making it an effective method for hiding data within seemingly innocuous text. By adding spaces or tabs at the end of lines in a document, SNOW allows for the encoding of messages without altering the visible text significantly, thus maintaining the original appearance of the document.

Other utilities like OpenStego, Invisible Secrets, and Steghide are known for different techniques of steganography. OpenStego, for example, specializes in hiding data within images and files, while Invisible Secrets offers various encryption and steganography methods, but does not focus exclusively on ASCII text through whitespace. Similarly, Steghide is used primarily for embedding data in image and audio files, rather than in plain text. Each of these serves distinct purposes and employs different methodologies, thereby highlighting the unique functionality of SNOW in the context of hiding information within ASCII text.