URL parameter from the API explorer with shared secret set to 81LqkNkvy
:
...&hash=80c887e839d79dc38248ed4cda4b6ad401f57305&ts=1391434954
In Ruby:
sharedsecret = '81LqkNkvy'
timestamp = 1391434954
require 'digest'
Digest::SHA1.hexdigest(sharedsecret + timestamp.to_s)
#=> "80c887e839d79dc38248ed4cda4b6ad401f57305"
And to get the current timestamp:
timestamp = Time.now.to_i
#=> 1391434369
Note that the hash changes every second.