B06902097 資工三 楊皓丞
Reference: D. Das, S. Meiser, E. Mohammadi, and A. Kate, “Anonymity trilemma: Strong anonymity, low bandwidth overhead, low latency—choose two,” Proceedings of IEEE S&P 2018 (to appear), San Francisco, CA, USA, May 2018. Available: https://eprint.iacr.org/2017/954
Alice
Eve
Oliver
Anonymous set
Alice
Eve
Oliver
Low Anonymity
High Anonymity
Strong Anonymity
Low Bandwidth Overhead
Low Latency Overhead
mix-nets
DC-nets
Tor
Can we achieve this?
No
Alice
Eve
Oliver
Bob
Alice or Bob?
Alice
Eve
Alice
Eve
Non-compromising | Compromising | |
Synchronized | ||
Unsynchronized |
Most simple!
Alice
Eve
Bob
Alice!
Alice
Eve
Bob
I don't know...
Alice
Eve
Bob
if \(l=4\):
I don't know...
if \(l=3\):
Alice!
\(r\)
\(t_1\)
\(t_2\)
\(t_0\)
\(t_3\)
\(t_4\)
\(t_5\)
\(r-l\)
Alice sends
Eve receives
Bob sends a message inside this interval
Challenge message passes through a honest node in this interval
If Invariant 1 doesn't hold, \(A_{paths}\) wins with probability 1
Alice
Eve
Bob
I don't know...
Carol
Alice
Eve
Bob
I don't know...
Carol
Alice
Eve
Bob
If \(u_0\) or \(u_1\) is Carol, I win
Carol
Non-negligible
advantage!
\(l\)
\(\beta\)
mix-net
Tor
DC-net
\(O(N)\)
\(O(1)\)
\(O(\frac{1}{N})\)
grey area: \(2l\beta < 1 - \epsilon\)
no strong anonymity
\(O(1)\)