RE: https://mastodon.social/@arstechnica/116518027082154811

This technique is commonly used for insider detection. Plant a unique canary in a datasource someone has access to and see which canary shows up and you have the leaker.

Another technique inverted to this purpose to spot manipulation without using obvious hashes or digital signatures is to insert a specific message into a plaintext that may be formatted wrong or not comply with the uniformity then get a HMAC signature out of it. Loop through the data and check if the MAC is created. This is called Chaffing and Winnowing:
https://en.wikipedia.org/wiki/Chaffing_and_winnowing

#cryptography #insiderdetection #espionage #dataintegrity #manipulation