4 ms·

Horcruxes are just a layer of security. If you want to further encrypt (or do more steganography) on the messages then it is not hard to add that too depending

Horcruxes are just a layer of security. If you want to further encrypt (or do more steganography) on the messages then it is not hard to add that too depending on your threat model and paranoia level. Horcruxes provide a unique solution to the problem of dragnets and increase costs of hacking your device even for governments.

maqp 6y ago
Horcruxes are just a layer of security. Sure, but the problem it solves is not the problem that needs addressing. Ciphertext and key delivery can already be done safely with E2EE apps like Signal. Metadata can be eliminated with e.g. Tor Onion Services. Your apps relies on QR-codes to exchange data, the same channel can be used to authenticate Signal endpoints and/or exchange PSKs, no need for SSS. Goal for information theoretic security is fine but considering nobody is doing CT-only attacks against modern algorithms anyway, the easiest attack vector will be MITM attack or remote key exfiltration. E.g. Snowden has been very vocal in the past about NSAs of the world hacking endpoints, but has quieted a bit down wrt the matter, perhaps he realized that was too high bar for average users who still benefit from incremental security from Signal etc.
- ljlolel 6y ago
  Pleas read through the whole doc. In many places it describes how it increases the cost of device hacking using 0-days significantly. There are limited other solutions for this, whereas Horcruxes are cheap and easy to implement.
  - maqp 6y ago
    The thing is, for the Horcrux to have any effect at all you need at least three devices per endpoint. And at that point using split TCB architecture is much better as under some assumptions it's provably secure against remote key exfiltration. See my work on TFC here: https://github.com/maqp/tfc https://github.com/maqp/tfc
vii 6y ago
The idea of layering security is very powerful, acknowledged in this "Network Operations Division Cryptographic Requirements" document https://wikileaks.org/ciav7p1/cms/files/NOD%20Cryptographic%20Requirements%20v1.1%20TOP%20SECRET.pdf https://wikileaks.org/ciav7p1/cms/files/NOD%20Cryptographic%... > Certificate validation must not be performed against any standard SSL root CAs. > implement an inner cryptostream within the SSL tunnel transfer People often state that you should not roll your own crypto. Definitely, you look foolish for making a mistake doing your own thing. However, adding your own layer on top of a standard one seems safe and likely to slow an adversary down considerably. Adding a layer below to encrypt data before the standard algorithm gets it has some risks (e.g. could leak in some complex way like a timing attack) but it also protects against a compromise in the implementation of the standard algorithm. Adding the Horcrux layer of multiple channels does seem to increase security at the cost of creating a new unvalidated magic wand that then becomes the attack surface - and another significant cost in that it is not user friendly and involves considerable effort per message. There are ways of implementing greater security at high cost, e.g. point-to-point communications off network. The question is if the extra effort confers any benefit. Sometimes just the fact that two parties are communicating is valuable knowledge and this Horcrux mechanism actually makes that easier to detect as it occurs across multiple systems.
- ljlolel 6y ago
  All good points, agreed with all. > Sometimes just the fact that two parties are communicating is valuable knowledge and this Horcrux mechanism actually makes that easier to detect as it occurs across multiple systems. Steganography can alleviate that red flag.

maqp 6y ago

Horcruxes are just a layer of security. Sure, but the problem it solves is not the problem that needs addressing. Ciphertext and key delivery can already be done safely with E2EE apps like Signal. Metadata can be eliminated with e.g. Tor Onion Services. Your apps relies on QR-codes to exchange data, the same channel can be used to authenticate Signal endpoints and/or exchange PSKs, no need for SSS. Goal for information theoretic security is fine but considering nobody is doing CT-only attacks against modern algorithms anyway, the easiest attack vector will be MITM attack or remote key exfiltration. E.g. Snowden has been very vocal in the past about NSAs of the world hacking endpoints, but has quieted a bit down wrt the matter, perhaps he realized that was too high bar for average users who still benefit from incremental security from Signal etc.

ljlolel 6y ago
Pleas read through the whole doc. In many places it describes how it increases the cost of device hacking using 0-days significantly. There are limited other solutions for this, whereas Horcruxes are cheap and easy to implement.
- maqp 6y ago
  The thing is, for the Horcrux to have any effect at all you need at least three devices per endpoint. And at that point using split TCB architecture is much better as under some assumptions it's provably secure against remote key exfiltration. See my work on TFC here: https://github.com/maqp/tfc https://github.com/maqp/tfc

vii 6y ago

The idea of layering security is very powerful, acknowledged in this "Network Operations Division Cryptographic Requirements" document https://wikileaks.org/ciav7p1/cms/files/NOD%20Cryptographic%20Requirements%20v1.1%20TOP%20SECRET.pdf https://wikileaks.org/ciav7p1/cms/files/NOD%20Cryptographic%... > Certificate validation must not be performed against any standard SSL root CAs. > implement an inner cryptostream within the SSL tunnel transfer People often state that you should not roll your own crypto. Definitely, you look foolish for making a mistake doing your own thing. However, adding your own layer on top of a standard one seems safe and likely to slow an adversary down considerably. Adding a layer below to encrypt data before the standard algorithm gets it has some risks (e.g. could leak in some complex way like a timing attack) but it also protects against a compromise in the implementation of the standard algorithm. Adding the Horcrux layer of multiple channels does seem to increase security at the cost of creating a new unvalidated magic wand that then becomes the attack surface - and another significant cost in that it is not user friendly and involves considerable effort per message. There are ways of implementing greater security at high cost, e.g. point-to-point communications off network. The question is if the extra effort confers any benefit. Sometimes just the fact that two parties are communicating is valuable knowledge and this Horcrux mechanism actually makes that easier to detect as it occurs across multiple systems.

ljlolel 6y ago
All good points, agreed with all. > Sometimes just the fact that two parties are communicating is valuable knowledge and this Horcrux mechanism actually makes that easier to detect as it occurs across multiple systems. Steganography can alleviate that red flag.