# File lib/rubygems/security.rb, line 401
    def self.trusted_cert_path(cert, opt = {})
      opt = Gem::Security::OPT.merge(opt)

      # get digest algorithm, calculate checksum of root.subject
      algo = opt[:dgst_algo]
      dgst = algo.hexdigest(cert.subject.to_s)

      # build path to trusted cert file
      name = "cert-#{dgst}.pem"

      # join and return path components
      File::join(opt[:trust_dir], name)
    end