Media channel monitoring to prove content presentation

A system for providing a blockchain-based proof of presentation of content on a media channel, the system comprising:

• a blockchain;
• a generator configured to generate at least first, second, and third parameters, wherein the first and second parameters are input parameters and the third parameter is calculated as an output parameter of a one-way cryptographic function,
• the generator configured to incorporate the first and third parameters into a first type of block and append the first type of block to the blockchain;
• an embedder which receives the content and embeds the second parameter into the content to produce tainted content;
• and
• a probe configured to monitor the media channel for the tainted content and to extract the second parameter from the tainted content,
• wherein the probe is further configured to perform a test on a condition of the one-way function using the first and third parameters extracted from the first type of block of the blockchain and the second parameter extracted from the tainted content,
• wherein the probe further comprises:
• a tuner configured to monitor the media channel for the tainted content;
• a watermark extractor configured to extract the second parameter the received tainted content;
• and
• a decision unit configured to access the blockchain and test challenge blocks in the blockchain until the first and third parameters in a challenge block matches the extracted second parameter by meeting the condition of the test of the one-way cryptographic function.