core.clj

(ns md5.core
  (:require [clojure.core.reducers :as r]
            [clojure.string :as s])
  (:import [java.security MessageDigest]
           [javax.xml.bind DatatypeConverter]))

(defn ^String hexdigest [^String s]
  (let [digester (MessageDigest/getInstance "MD5")]
    (. digester update (.getBytes s))
    (DatatypeConverter/printHexBinary (.digest digester))))

(defn ^Boolean match? [^String salt ^String pass ^String digest]
  (= digest (hexdigest (str salt "$" pass))))

(defn ^String pad [^Integer n x]
  (if (> n (.length (str x)))
    (recur n (str 0 x))
    (str x)))

(defn find-password [salt pw]
  (->> (range 1000000)
       (map #(pad 6 %))
       (filter #(match? salt % pw))))
(time (dotimes [n 1000000]
   (pad 6 n)))

(time (into [] (find-password "hoge" (s/upper-case "4b364677946ccf79f841114e73ccaf4f"))))