acid-info
/
vac.dev
mirror of https://github.com/acid-info/vac.dev.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

fix(relay anonymity): clarify attack

This commit is contained in:
ksr 2022-07-22 09:46:14 +02:00
parent d74514e618
commit 3c6e0d49bd
No known key found for this signature in database
GPG Key ID: E4EB341A3BB26FA5
1 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
research/2022-07-15-relay-anonymity.md
View File

@ -263,17 +263,23 @@ Further, replay attacks will be punished by [RLN](https://rfc.vac.dev/spec/17/)
### Neighbourhood Surveillance
This attack can be performed by a single node attacker that is connected to peers of the victim node $v$ with respect to a specific topic mesh.
This attack can be performed by a single node attacker that is connected to all peers of the victim node $v$ with respect to a specific topic mesh.
The attacker also has to be connected to $v$.
In this position, the attacker will receive messages $m_v$ sent by $v$ both on the direct path from $v$, and on indirect paths relayed by peers of $v$.
It will also receive messages $m_x$ that are not sent by $v$. These messages $m_x$ are relayed by both $v$ and the peers of $v$.
Messages that are received (significantly) faster from $v$ are very likely messages that $v$ sent, because for these messages the attacker is one hop closer to the source.
Messages that are received (significantly) faster from $v$ than from any other of $v$'s peers are very likely messages that $v$ sent,
because for these messages the attacker is one hop closer to the source.
The attacker can (periodically) measure latency between itself and $v$, and between itself and the peers of $v$ to get more accurate estimates for the expected timings.
An AS attacker (and if the topology allows, even a local attacker) could also learn the latency between $v$ and its well-behaving peers.
An active AS attacker could also increase the latency between $v$ and its peers to make the timing differences more prominent.
This, however, might lead to $v$ switching to other peers.
This attack cannot (reliably) distinguish messages $m_v$ sent by $v$ from messages $m_y$ relayed by peers of $v$ the attacker is not connected to.
Still, there are hop-count variations that might be leveraged.
Messages $m_v$ always have a hop-count of 1 from $v$ to the attacker, while all other paths are longer.
Messages $m_y$ might have the same hop-count on the path from $v$ as well as from other paths.
### Controlled Neighbourhood
If a multi node attacker manages to control all peers of the victim node, it can trivially tell which messages originated from $v$.