
Black hats steal codesigning keys from software whitelisting antimalware firm. Pretty audacious
(tags: malware security whitelisting av)
How did I do the Starwars Traceroute?
It is accomplished using many vrfs on 2 Cisco 1841s. For those less technical, VRFs are essentially private routing tables similar to a VPN. When a packet destined to 216.81.59.173 (AKA obiwan.scrye.net) hits my main gateway, I forward it onto the first VRF on the “ASIDE” router on 206.214.254.1. That router then has a specific route for 216.81.59.173 to 206.214.254.6, which resides on a different VRF on the “BSIDE” router. It then has a similar set up which points it at 206.214.254.9 which lives in another VPN on “ASIDE” router. All packets are returned using a default route pointing at the global routing table. This was by design so the packets TTL expiration did not have to return fully through the VRF Maze. I am a consultant to Epik Networks who let me use the Reverse DNS for an unused /24, and I used PowerDNS to update all of the entries through mysql. This took about 30 minutes to figure out how to do it, and about 90 minutes to implement.
(tags: vrfs routing networking hacks starwars traceroute rdns ip)
Realtime Analytics in Scala [slides, PDF]
some good approximation/streaming algorithms and tips on Scala implementation
(tags: streams algorithms approximation coding scala slides)
‘E?cient Computation of Frequent and Topk Elements in Data Streams’ [paper, PDF]
The SpaceSaving algorithm to compute topk in a stream. I’ve been asking a variation of this problem as an interview question for a while now, pretty cool to find such a neat solution. Pity neither myself nor anyone I’ve interviewed has come up with it ;)
(tags: spacesaving approximation streams streamprocessing cep papers pdf algorithms)

ASLlicensed open source library of streamprocessing/approximation algorithms: countmin sketch, spacesaving topk, cardinality estimation, LogLog, HyperLogLog, MurmurHash, lookup3 hash, Bloom filters, qdigest, stochastic topk
(tags: algorithms coding streams cep streamprocessing approximation probabilistic spacesaving topk cardinality estimation bloomfilters qdigest loglog hyperloglog murmurhash lookup3)
‘Medians and Beyond: New Aggregation Techniques for Sensor Networks’ [paper, PDF]
‘We introduce Quantile Digest or qdigest, a novel data structure which provides provable guarantees on approximation error and maximum resource consumption. In more concrete terms, if the values returned by the sensors are integers in the range [1;n], then using qdigest we can answer quantile queries using message size m within an error of O(log(n)/m). We also outline how we can use qdigest to answer other queries such as range queries, most frequent items and histograms. Another notable property of qdigest is that in addition to the theoretical worst case bound error, the structure carries with itself an estimate of error for this particular query.’
(tags: qdigest algorithms streams approximation histograms median percentiles quantiles)
Russia’s antichildporn internet blocklist allegedly being used for general censorship
Allegedly being used to censor political and anticorruption journalism, and a Russian wikipedialike site for hosting an article about suicide
(tags: censorship featurecreep russia politics blocklists)
HyperLogLog++: Google’s Take On Engineering HLL
Google and AggregateKnowledge’s improvements to the HyperLogLog cardinality estimation algorithm
(tags: hyperloglog cardinality estimation streaming streamprocessing cep)
Links for 20130209
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