(import-os-error-syscall %crypt (key salt) "scm_crypt")

(define (crypt key salt)
  (let* ((allowed-char-set  (rx (| alpha digit "." "/")))
	 (salt-regexp  (rx (: ,allowed-char-set ,allowed-char-set))))
    (if (not (= (string-length salt) 2)) (error "salt must have length 2"))
    (if (not (regexp-search? salt-regexp salt))
	(error "illegal char in salt " salt))
    (if (> (string-length key) 8) (error "key too long "  (string-length key)))
    (%crypt key salt)))