Lately we had to analyze QR-Codes in a pentest. Those held some random data which was used as a token for login and we wanted to know if that data was really random.
If you ever worked with the Burp Suite you may know the Burp Sequencer, which offers some statistical analysis regarding the randomness of tokens which appear in requests (you just have to tell Burp what or where the token is). In our case the QR-Code was delivered as an inline-image in HTML to the browser, like this:
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