4 ms·

Okay, then I set the date on my computer to year the 2124. Now the DRM is unlocked! You can't build a "time lock" with just encryption primitives. Even if you

Okay, then I set the date on my computer to year the 2124. Now the DRM is unlocked! You can't build a "time lock" with just encryption primitives. Even if you could build a time lock with just encryption primitives, we don't know when the copyright will expire until the original author has died, since copyright term is life + 70 years. Someone would have to run a server that specifically chooses to start serving the keys on that date, which is an absurd notion given how absurdly long copyright lasts these days. If the federal government were interested in passing a law that required this, I'm sure the Library of Congress could run such a server, but no such law exists.

alexvoda 3y ago
Not at all absurd. Maybe not through crypto but otherwise perfectly achievable. No reason to achieve this within a file. If you really want to, some fancy solution involving blockchains and smart contracts is probably possible but there is no need. Require by law all who desire copyright protection to register the work with a governmental agency and place a copy of the work in escrow at an archive as a condition. The archive knows when the copyright expires and starts serving the work to the public from that point forward. This is what to do if a state cares about public domain. The status quo of corporations abandoning works to bit rot, actual rot, misplacement or fires for decades is strictly worse.
- coder543 3y ago
  >> If the federal government were interested in passing a law that required this, I'm sure the Library of Congress could run such a server, but no such law exists. > Require by law all who desire copyright protection to register the work with a governmental agency and place a copy of the work in escrow at an archive as a condition. You’re just repeating what I already wrote. By all means, call your representatives.
shkkmo 3y ago
> set the date on my computer to year the 2124. Now the DRM is unlocked! It's the same. "Fail closed" means you can "just" set the system time to be before the expiration date, "fail open" means you can just set the system time to be after. Either way, having an expiring decryption key is just security theater that harms users.
jasonjayr 3y ago
I imagine most systems needing a trusted clock do so with a positive GPS lock. Spoofing that now gets you in trouble with the FCC as well as the DMCA.
- marksomnian 3y ago
  No need to spoof the GPS signal, pop open the lid and replace the GPS chip with one that outputs an attacker-controlled time signal. I suppose it could encrypt this signal with some certificate burned into the silicon, but that could still (slowly and painfully) be reverse-engineered. GP’s point stands, you can’t enforce a time lock with cryptography primitives. That’s the fundamental issue with DRM - you’re trying to restrict someone from getting your ciphertext, while at the same time allowing them to get to it if they meet certain (non-cryptographic) conditions, which standard cryptography just can’t do.

alexvoda 3y ago

Not at all absurd. Maybe not through crypto but otherwise perfectly achievable. No reason to achieve this within a file. If you really want to, some fancy solution involving blockchains and smart contracts is probably possible but there is no need. Require by law all who desire copyright protection to register the work with a governmental agency and place a copy of the work in escrow at an archive as a condition. The archive knows when the copyright expires and starts serving the work to the public from that point forward. This is what to do if a state cares about public domain. The status quo of corporations abandoning works to bit rot, actual rot, misplacement or fires for decades is strictly worse.

coder543 3y ago
>> If the federal government were interested in passing a law that required this, I'm sure the Library of Congress could run such a server, but no such law exists. > Require by law all who desire copyright protection to register the work with a governmental agency and place a copy of the work in escrow at an archive as a condition. You’re just repeating what I already wrote. By all means, call your representatives.

shkkmo 3y ago

> set the date on my computer to year the 2124. Now the DRM is unlocked! It's the same. "Fail closed" means you can "just" set the system time to be before the expiration date, "fail open" means you can just set the system time to be after. Either way, having an expiring decryption key is just security theater that harms users.

jasonjayr 3y ago

I imagine most systems needing a trusted clock do so with a positive GPS lock. Spoofing that now gets you in trouble with the FCC as well as the DMCA.

marksomnian 3y ago
No need to spoof the GPS signal, pop open the lid and replace the GPS chip with one that outputs an attacker-controlled time signal. I suppose it could encrypt this signal with some certificate burned into the silicon, but that could still (slowly and painfully) be reverse-engineered. GP’s point stands, you can’t enforce a time lock with cryptography primitives. That’s the fundamental issue with DRM - you’re trying to restrict someone from getting your ciphertext, while at the same time allowing them to get to it if they meet certain (non-cryptographic) conditions, which standard cryptography just can’t do.