Final answer:
The technique known as 'snow' uses whitespace in documents to conceal messages as part of the steganography process.
Step-by-step explanation:
The Steganography technique that uses Whitespace to hide secret messages is known as snow. This method involves taking advantage of the white spaces at the ends of lines to encode messages. The name 'snow' is actually an acronym for Steganographic Nature Of Whitespace. Each space or tab at the end of the line can be manipulated to represent a different bit of the secret message, thus enabling the message to be hidden in plain sight without any perceivable difference in the document to the ηaked eye.