gatekeeper

gatekeeper.py

#!/usr/bin/python

from tkinter import *


PWD_LENGTH = 16


tokens = ''.join((
    'abcdefghijklmnopqrstuvwxyz',
    'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
    '0123456789'))


def to_uint64(x):
    return x & 0xffffffffffffffff


def to_uint32(x):
    return x & 0xffffffff


class generator(object):

    def __init__(self):
        self.seed = 1

    def next_char(self):
        # xor shift
        self.seed  = to_uint64(self.seed)
        self.seed ^= to_uint64(self.seed >> 12)
        self.seed ^= to_uint64(self.seed << 25)
        self.seed ^= to_uint64(self.seed >> 27)
        # whiten
        v = to_uint64(self.seed * 2685821657736338717)
        # bring down into lower bits
        v = to_uint32((v >> 24) ^ (v >> 16) ^ (v >> 8) ^ v)
        # 32bit abs it
        v = ((v ^ 0xffffffff) + 1) if v & 0x80000000 else v
        # index into token array
        return tokens[v % len(tokens)]

    def run(self, a, b):
        self.seed = 1
        al = len(a)
        bl = len(b)
        assert (al > 0 and bl > 0)
        maxl = max(al, bl)
        for i in range(maxl):
            oa = ord(a[i % al])
            ob = ord(b[i % bl])
            self.seed = to_uint64(self.seed * oa + ob)
        out = ''
        for i in range(PWD_LENGTH):
            out += self.next_char()
        return out


def self_check():
    pwd = generator()
    assert (pwd.run('test', 'hello_there') == 'gbueMBr6PZTfwsRF')
    assert (pwd.run('more_testing', 'foobar') == 'IkiNM6u1jNUH4o90')


def on_clear(args):
    root, ent_pwd, ent_url = args
    ent_pwd.delete(0, END)
    ent_url.delete(0, END)


def on_copy(args):
    root, ent_pwd, ent_url = args
    pwd = generator()
    out = pwd.run(ent_pwd.get(), ent_url.get())
    root.clipboard_clear()
    root.clipboard_append(out)
    ent_pwd.delete(0, END)
    ent_url.delete(0, END)


def main():
    root = Tk()
    root.wm_title('gatekeeper')

    ent_pwd = Entry(root, show='*')
    ent_pwd.pack(side=TOP)

    ent_url = Entry(root)
    ent_url.pack(side=TOP)

    but = Button(root,
                 text='clear',
                 width=10,
                 command=lambda: on_clear((root,
                                           ent_pwd,
                                           ent_url)))
    but.pack(side=LEFT)

    but = Button(root,
                 text='copy',
                 width=10,
                 command=lambda: on_copy((root,
                                          ent_pwd,
                                          ent_url)))
    but.pack(side=LEFT)

    # enter tkinter main loop
    mainloop()


self_check()
main()