(use message-digest md5 srfi-13)
(define DOORID "uqwqemis")

(define (matching-hash idstr)
  (let ((h (message-digest-string
            (md5-primitive)
            idstr)))
    (if (and (string-every #\0 h 0 5)
             (< (string->number (substring h 5 6) 16) 8))
        (cons (string->number (substring h 5 6))
              (string-ref h 6))
        #f)))

(define (findpass id)
  (let loop ((n 0)
             (pass (make-string 8 #\g))
             (cntr 8))
    (if (= cntr 0)
        pass
        (let ((h (matching-hash
                  (string-append id
                                 (number->string n)))))
          (if (and h (char=? (string-ref pass (car h)) #\g))
              (loop (fx+ n 1) (and (string-set! pass (car h) (cdr h)) pass)
                    (- cntr 1))
              (loop (fx+ n 1) pass cntr))))))

(findpass DOORID)