alt Hacker News> define your "usage token" as H(private_key|service_domain_name|date|4-bit_counter)
But how are you preventing multiple services from using the same value for service_domain_name because they're cooperating to correlate your use?
> define your "usage token" as H(private_key|service_domain_name|date|4-bit_counter)
But how are you preventing multiple services from using the same value for service_domain_name because they're cooperating to correlate your use?
Because-- in this hypothetical-- your user agent restricts the usage to the name displayed on the screen and also because your agent won't send the same value twice either (it'll increment the counter or tell you that its run out of tokens).