Iāve done some explanation of this (initial results are repeated in the table below for convenience)
GROUP_SIZE = 8
Test 1 2 3 4 5 | Avg
T Nodes 20297 67517 49797 67960 68381 | 54790
T Nodes (%) 16.9 40.3 33.2 40.5 40.6 | 34.3
Sections 1961 2233 2115 2206 2211 | 2145
T Elders 13 296 172 333 313 | 225
T Elders (%) 0.08 1.66 1.02 1.89 1.77 | 1.28
Test 1
This test had the attacker owning 17% of all nodes and 0.08% of all elders to disrupt the network. This is a surprisingly low number of attacking vaults to cause disruption.
The attacked section age distribution is shown below (* means attacker):
8 6 5* 5* 5 5 5* 5 | 5 5 5 5 4* 4 4 4 4 4* 4 4 3 3 3 3 3 3* 3* 3* 3 3* 3 3 3 3 3 3 1*
Itās quite a small section, only 37 vaults, compared to an average of 61 vaults.
The attacker got very lucky in resolving the tiebreaker for age.
For comparison, hereās some non-attacked sections
Youngest Section (least total age)
7 7 6 6 6 6 6 5 | 5 5 5 4 4 4 4 3 5
Average Section
7 6 6 5* 5 5 5 5 | 5 5 5 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3* 3 3* 3* 3 3* 3 3* 3 3... (31 more vaults)
Oldest Section (most total age)
11 11 10 9 9 7 7 7 | 7 7 7 6 6 6 6 6 6 6 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 4 4 4 4... (207 more vaults)
Test 4
Test 4 is interesting because it had the highest number of attacked elders before a disruption happened. Despite that, less than 2% of all elders were needed by the attacker to cause disruption, which is also fairly low.
Attacked section age distribution:
7 6 6 6* 6 6* 6 5* | 5 5 5 5 5 5 5 5 5 4 4* 4 4 4* 4 4 4 4 4 4 4 4 4 4 4 4 ... (49 more vaults)
Itās slightly above average size section, 83 vaults, compared to an average size of 76 vaults.
The attacker was really lucky again with the age tiebreaker.
Youngest Section
8 8 6 6 6 6 6 6 | 5 4 4 3 3 3 3 1* 1 1* 1* 1*
Average Section
6 6 6 6 6 6 6 5 | 5 5 5 5 5 5 5 5 4* 4 4 4 4 4 4 4* 4 4 4 4 4 4* 4 4 4 3* 3* ... (47 more vaults)
Oldest Section
7 7 7 7 6 6 6 6 | 6* 6 5 5 5 5 5 5 5 5 5 5 5 5 5 5* 5 5 4 4 4 4 4 4 4 4 4 4 4 ... (163 more vaults)
Changing to 31 elders instead of 8
GROUP_SIZE = 31
Test 1 2 3 4 5 | Avg
T Nodes 134077 136771 155184 167490 121992 | 143103
T Nodes (%) 57.3 57.8 60.8 62.6 55.0 | 58.7
Sections 1027 1022 1041 1051 1023 | 1033
T Elders 3094 3128 3755 4203 2729 | 3382
T Elders (%) 9.72 9.87 11.64 12.90 8.61 | 10.55
Much closer to the expected calculated 12% for disruption from the birthday problem.
I think itās possible. Itās imaginable that a single operator might suddenly try adding huge numbers of vaults for a whole day / week (considering the disallow rule means entry is competitive so the attacker ends up taking almost all new spots because they dominate all the queues). For a young network this would appear quite similar to pure attacking vaults being added to the network.
But on the other hand, I can agree with you itās not real life stuff; hopefully the network participation is vigorous so thereās no monopoly on attacks, even if 99% of joining activity is considered to by āan attackerā (from some vast number of attackers).
To me the unimaginable part is not āonly baddies adding nodesā itās only one baddie adding all bad nodes.
Say we end up with only 10 of the āworstā companies ātotally owningā the network; google, microsoft, apple, facebook, amazon, twitter, ebay, wechat, baidu, reddit - their window to disrupt the network becomes very small due to competition for section membership (assuming they even want to cause disruption in the first place).
Perhaps another way to look at it is āhow many non-malicious nodes do we need to prevent disruptionā. And achieving that is probably easier than detecting and evicting malicious nodes. Given two approaches to the same problem 1) recruit +90% neutral nodes or 2) prevent +10% malicious nodes Iād say 1) is much easier to achieve than 2) even though it solves the same problem.
Yes, and merging, and age tiebreaking, and relocations, and best neighbour targeting, but not relocation tiebreaking (todo).
If we have 1 PB of ābenevolentā chunks (total) uploaded in the period before going āliveā spread over 100K vaults, thatās 10 GB per vault. I think there will be many more vaults than 100K very quickly once the network is live, mainly because 10 GB per vault is too high for manageable churn (at least thatās how I imagine it, open to debate on what the early network may look like but a bit out of scope for this topic perhaps).