class Net::SMTP

def cram_secret(secret, mask) 

def cram_secret(secret, mask)
  secret = digest_class::MD5.digest(secret) if secret.size > CRAM_BUFSIZE
  buf = secret.ljust(CRAM_BUFSIZE, "\0")
  0.upto(buf.size - 1) do |i|
    buf[i] = (buf[i].ord ^ mask).chr
  end
  buf
end