3 ms·

https://en.wikipedia.org/wiki/One-time_pad https://en.wikipedia.org/wiki/One-time_pad

by Jerrrrrrry 2y ago

tjohns 2y ago
And just how are you delivering the key material for your one-time pad?
- shermantanktop 2y ago
  It's OTPs all the way down.
- Jerrrrrrry 2y ago
  Doesn't matter. Literally, could be entangled quantum photo-carrier pigeons. x ⊕ y = z z ⊕ x = y y ⊕ z = x Assuming another Out-of-Bound communication channel, all communication channels are provably safe. https://en.wikipedia.org/wiki/One-time_pad#Perfect_secrecy https://en.wikipedia.org/wiki/One-time_pad#Perfect_secrecy
  - echoangle 2y ago
    If you have the Out-of-Band communication channel to transmit your OTP (which has to have the same size as the data itself), you can just transmit the data using this method and skip the other channel.
    - teddyh 2y ago
      True, but you might have a secure OOB channel for a limited time. In that case, you can transfer an arbitrarily large OTP over the secure channel, to be used later, in small pieces, when you do not have a secure channel available.
dredmorbius 2y ago
Signed checksums are generally sufficient to validate integrity. You could GPG encrypt / sign the entire payload as well if desired, though that requires recipients to have their own keys. Some 33 years after the introduction of PGP, this remains a significant stumbling block.
- Jerrrrrrry 2y ago
  signed keys You just described using Out-of-Band communication, without using the words Some 33 years after the introduction of PGP, this remains a significant stumbling block. 'This problem was given the name the Two Generals Paradox by Jim Gray[8] in 1978 in "Notes on Data Base Operating Systems" starting on page 465.' https://en.wikipedia.org/wiki/Two_Generals%27_Problem https://en.wikipedia.org/wiki/Two_Generals%27_Problem
  - dredmorbius 2y ago
    Payload sizes of an OS distribution and a GPG signature / checksum differ by six or more orders of magnitude. The validation checks themselves can be readily publicly distributed. Though of course if desired, they can also be distributed with media, or in a separate postal mailing. PKI leverages OOB comms such that a single OOB exchange can validate an entire further chain of messages.
    - Jerrrrrrry 2y ago
      Payload sizes irrelevant validation checks themselves can be readily publicly distributed how do you know which one? with the a priori key exchange / Out-of-Band communication? distributed with media backdoor/spoofable/resignable >separate postal mailing finally, full circle. PKI leverages OOB comms such that a single OOB exchange can validate an entire further chain of messages. yes, hashing hashes and bloom filters arent novel. ultimately, the only solution we have so far is: https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange#Public_key https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exc...

https://en.wikipedia.org/wiki/One-time_pad https://en.wikipedia.org/wiki/One-time_pad

tjohns 2y ago

And just how are you delivering the key material for your one-time pad?

shermantanktop 2y ago
It's OTPs all the way down.
Jerrrrrrry 2y ago
Doesn't matter. Literally, could be entangled quantum photo-carrier pigeons. x ⊕ y = z z ⊕ x = y y ⊕ z = x Assuming another Out-of-Bound communication channel, all communication channels are provably safe. https://en.wikipedia.org/wiki/One-time_pad#Perfect_secrecy https://en.wikipedia.org/wiki/One-time_pad#Perfect_secrecy
- echoangle 2y ago
  If you have the Out-of-Band communication channel to transmit your OTP (which has to have the same size as the data itself), you can just transmit the data using this method and skip the other channel.
  - teddyh 2y ago
    True, but you might have a secure OOB channel for a limited time. In that case, you can transfer an arbitrarily large OTP over the secure channel, to be used later, in small pieces, when you do not have a secure channel available.

dredmorbius 2y ago

Signed checksums are generally sufficient to validate integrity. You could GPG encrypt / sign the entire payload as well if desired, though that requires recipients to have their own keys. Some 33 years after the introduction of PGP, this remains a significant stumbling block.

Jerrrrrrry 2y ago
signed keys You just described using Out-of-Band communication, without using the words Some 33 years after the introduction of PGP, this remains a significant stumbling block. 'This problem was given the name the Two Generals Paradox by Jim Gray[8] in 1978 in "Notes on Data Base Operating Systems" starting on page 465.' https://en.wikipedia.org/wiki/Two_Generals%27_Problem https://en.wikipedia.org/wiki/Two_Generals%27_Problem
- dredmorbius 2y ago
  Payload sizes of an OS distribution and a GPG signature / checksum differ by six or more orders of magnitude. The validation checks themselves can be readily publicly distributed. Though of course if desired, they can also be distributed with media, or in a separate postal mailing. PKI leverages OOB comms such that a single OOB exchange can validate an entire further chain of messages.
  - Jerrrrrrry 2y ago
    Payload sizes irrelevant validation checks themselves can be readily publicly distributed how do you know which one? with the a priori key exchange / Out-of-Band communication? distributed with media backdoor/spoofable/resignable >separate postal mailing finally, full circle. PKI leverages OOB comms such that a single OOB exchange can validate an entire further chain of messages. yes, hashing hashes and bloom filters arent novel. ultimately, the only solution we have so far is: https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange#Public_key https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exc...