lib/util.js
function sha2(str) {
  var md = forge.md.sha256.create();
  md.update(str);
  return md.digest().toHex()
}
function sha2(str) {
  var md = forge.md.sha256.create();
  md.update(str);
  return md.digest().toHex()
}
function sha2 ( str ) { var md = forge . md . sha256 . create ( ) ; md . update ( str ) ; return md . digest ( ) . toHex ( ) }
sha2 get the sha256 of a string
@param  {String} str the string
@return {String}     the hash
sha2 get the sha256 of a string