require 'digest/sha1'Digest::SHA1.hexdigest 'foo'
For a Base64 encoded hash, to validated an Oauth signature, I used
require 'base64'require 'hmac-sha1'Base64.encode64((HMAC::SHA1.new('key') << 'base').digest).strip
I created a helper gem which is a simple wrapper around some sha1 code
require 'rickshaw'> Rickshaw::SHA1.hash('LICENSE.txt') => "4659d94e7082a65ca39e7b6725094f08a413250a" > "hello world".to_sha1 => "2aae6c35c94fcfb415dbe95f408b9ce91ee846ed"