5 ms·

I wonder if there are cases where it's better to cut an enemy cable, as opposed to tapping it. I can't think of any, but this isn't my field.

henryfjordan 7y ago
Tapping the cable still allows the enemy to talk. Sometimes, if the enemy is trying to be sneaky, it's better to overhear them and thwart their efforts. Other times the enemy might be trying to coordinate a massive attack for which timing is key. It wouldn't matter if you overhear because you need to disrupt the attack before it starts. In that case it's better to not let the enemy communicate at all.
- ryacko 7y ago
  Still doesn’t explain why layer 1 encryption isn’t used for oceanic cables. Edit: I mean this from a timeless perspective, and slightly from the present day.
  - krastanov 7y ago
    In 1915!? Because mathematically sound encryption and the computational machinery to employ it did not exist back then.
    - dboreham 7y ago
      Hmm...sound encryption did exist: https://en.wikipedia.org/wiki/One-time_pad#History https://en.wikipedia.org/wiki/One-time_pad#History And computational machinery to implement it, at least for telegraph seems to have quite likely existed in 1915: https://patents.google.com/patent/US1310719 https://patents.google.com/patent/US1310719 (filing date 1917).
      - mindslight 7y ago
        A one time pad is not "sound encryption", as it lacks message integrity.
        ryacko 7y ago
        Layer 1 encryption doesn’t involve message integrity.
        mindslight 7y ago
        That's a weird assertion, but okay. My only point was that by the modern standards we take for granted, OTP/XOR is not really a cryptosystem but better thought of as a primitive. IMO for those just learning crypto, it's a red herring that hides the core functionality of modern cryptography (see: the common amateur reinvention of using a PRNG as a OTP). My answer to your main question is because encrypting layer 1 adds negligible security properties to the whole system (can't tap that link, but you can tap anywhere else), everything should already be encrypted at a higher level (for the previous reason, as well as integrity/authorization/etc), and that the bandwidth is too high (the entire point of packet switched networks is to do as little as possible in each node). Applied to the existing Internet, the only thing it would gain is hiding addressing metadata from an attacker who directly taps a link. A more effective general way of doing this would be something like onion source routing, where each router only knows the next hop. But once again the scalability problem, so the desire is better applied to an overlay network rather than convincing backbone providers to take this on - there is barely the impetus for IPv6.

henryfjordan 7y ago

Tapping the cable still allows the enemy to talk. Sometimes, if the enemy is trying to be sneaky, it's better to overhear them and thwart their efforts. Other times the enemy might be trying to coordinate a massive attack for which timing is key. It wouldn't matter if you overhear because you need to disrupt the attack before it starts. In that case it's better to not let the enemy communicate at all.

ryacko 7y ago
Still doesn’t explain why layer 1 encryption isn’t used for oceanic cables. Edit: I mean this from a timeless perspective, and slightly from the present day.
- krastanov 7y ago
  In 1915!? Because mathematically sound encryption and the computational machinery to employ it did not exist back then.
  - dboreham 7y ago
    Hmm...sound encryption did exist: https://en.wikipedia.org/wiki/One-time_pad#History https://en.wikipedia.org/wiki/One-time_pad#History And computational machinery to implement it, at least for telegraph seems to have quite likely existed in 1915: https://patents.google.com/patent/US1310719 https://patents.google.com/patent/US1310719 (filing date 1917).
    - mindslight 7y ago
      A one time pad is not "sound encryption", as it lacks message integrity.
      - ryacko 7y ago
        Layer 1 encryption doesn’t involve message integrity.
        mindslight 7y ago
        That's a weird assertion, but okay. My only point was that by the modern standards we take for granted, OTP/XOR is not really a cryptosystem but better thought of as a primitive. IMO for those just learning crypto, it's a red herring that hides the core functionality of modern cryptography (see: the common amateur reinvention of using a PRNG as a OTP). My answer to your main question is because encrypting layer 1 adds negligible security properties to the whole system (can't tap that link, but you can tap anywhere else), everything should already be encrypted at a higher level (for the previous reason, as well as integrity/authorization/etc), and that the bandwidth is too high (the entire point of packet switched networks is to do as little as possible in each node). Applied to the existing Internet, the only thing it would gain is hiding addressing metadata from an attacker who directly taps a link. A more effective general way of doing this would be something like onion source routing, where each router only knows the next hop. But once again the scalability problem, so the desire is better applied to an overlay network rather than convincing backbone providers to take this on - there is barely the impetus for IPv6.