# File lib/quiz1/t/solutions/Jim Menard/solitaire_cypher.rb, line 159
    def encrypt(str)
        @deck = @keyed_deck.dup
        answer = ''
        str.split(//).each { | c |
            if c == ' '
                answer << ' '
                next
            end

            msg_num = Card.chr_to_value(c)
            key = @deck.next_keystream
            sum = msg_num + key
            sum -= 26 if sum > 26
            answer << Card.value_to_chr(sum)
        }
        answer
    end