API sha1 hash generation not matching

Question

I'm getting from Slideshare API explorer which is working:

64f43b4be73bc11a15142c1ef5dab1130c5064cb

From SHA1 hashing of below string

81LqkNkvy1391428643

But when I use in Rails:

Digest::SHA1.hexdigest("81LqkNkvy1391428643")

I get:

1ef520bb53227b9edf691d47da653f93d232e16e

I cannot figure out why this is not matching.

According to Slideshare API link

http://www.slideshare.net/developers/documentation

It clearly says

hash: Set this to the SHA1 hash of the concatenation of the shared secret and the 
timestamp (ts). i.e. SHA1 (sharedsecret + timestamp). The order of the terms 
in the concatenation is important.

I thought I followed the instructions correctly. I also tried decryption of above SHA1 strings but had no luck so far.

What could be the issue here?

Answer 1

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.

Answer 2

Tried time stamp in milliseconds ?