How to enable https support in twitteR?

Question

I am trying to connect to twitter using the twitteR package in R. Script and results are below. Running R 3.1.2 64 bit on windows 8.1. Any suggestions about how to enable https? I've not found a solution on R-help or any other searchable source.

require(twitteR)
Loading required package: twitteR
Loading required package: ROAuth
Loading required package: RCurl
Loading required package: bitops
Loading required package: rjson
> cred <- OAuthFactory $ new( consumerKey = my.key, consumerSecret = my.secret, requestURL =' https:// api.twitter.com/ oauth/ request_token', accessURL =' https:// api.twitter.com/ oauth/ access_token', authURL =' https:// api.twitter.com/ oauth/ authorize')
> cred$handshake(cainfo = "C:/users/john/documents/twitter/cacert.pem")
Error in function (type, msg, asError = TRUE)  : 
  Protocol " https" not supported or disabled in libcurl

Answer 1

URL's for requestURL and following were specified with a single quote. When the single quotes were replaced with a double quote and spaces removed, the function worked on Windows.