Find out onion key lifetime from server descriptors:

First, parse fingerprints, publication times, and onion keys from server
descriptors to make subsequent analyses faster:

  $ javac ParseServerDescriptors.java
  $ java ParseServerDescriptors server-descriptor/2011/05 \
      > parsed-2011-05.csv

Sort the output by fingerprint, then by publication time:

  $ sort parsed-2011-05.csv > sorted-2011-05.csv

Extract first and last publication times of onion keys that we saw at
least twice.  Also include the fingerprint and calculate the number of
seconds between the two timestamps:

  $ javac ExtractOnionKeyLifetimes.java
  $ java ExtractOnionKeyLifetimes.java > onion-key-lifetimes.csv

Plot an ECDF and print out the onion keys that were in use for at least 10
days:

  $ R --slave -f onion-key-lifetimes.R

