reference the python code

1 files changed, 0 insertions, 159 deletions

diff --git a/programs/ls47.py b/programs/ls47.py
deleted file mode 100755
index 41a1405..0000000
--- a/programs/ls47.py
+++ /dev/null
@@ -1,159 +0,0 @@
-#!/usr/bin/python2
-# -*- coding: utf-8 -*-
-
-import random
-
-letters = "_abcdefghijklmnopqrstuvwxyz.0123456789,-+*/:?!'()"
-tiles = zip(letters, map(lambda x: (x / 7, x % 7), range(7 * 7)))
-padding_size = 10
-
-
-def check_key(key):
-    if len(key) != len(letters):
-        raise ValueError('Wrong key size')
-    cnts = {}
-    for c in letters:
-        cnts[c] = 0
-    for c in key:
-        if not c in cnts:
-            raise ValueError('Letter ' + c + ' not in LS47!')
-        cnts[c] += 1
-        if cnts[c] > 1:
-            raise ValueError('Letter ' + c + ' duplicated in key!')
-
-
-def find_ix(letter):
-    m = filter(lambda (l, pos): l == letter, tiles)
-    if len(m) != 1:
-        raise ValueError('Letter ' + letter + ' not in LS47!')
-    for (l, pos) in m:
-        return pos
-
-
-def find_pos(key, letter):
-    p = key.find(letter)
-    if p >= 0 and p < 7 * 7:
-        return (p / 7, p % 7)
-    raise ValueError('Letter ' + letter + ' not in key?!')
-
-
-def add_pos((ax, ay), (bx, by)):
-    return ((ax + bx) % 7, (ay + by) % 7)
-
-
-def sub_pos((ax, ay), (bx, by)):
-    return ((ax - bx) % 7, (ay - by) % 7)
-
-
-def find_at_pos(key, (row, col)):
-    return key[col + row * 7]
-
-
-def rotate_right(key, row, n):
-    mid = key[7 * row:7 * (row + 1)]
-    n = (7 - n % 7) % 7
-    return key[:7 * row] + mid[n:] + mid[:n] + key[7 * (row + 1):]
-
-
-def rotate_down(key, col, n):
-    lines = map(lambda i: key[i * 7:(i + 1) * 7], range(7))
-    lefts = map(lambda l: l[:col], lines)
-    mids = map(lambda l: l[col], lines)
-    rights = map(lambda l: l[col + 1:], lines)
-    n = (7 - n % 7) % 7
-    mids = mids[n:] + mids[:n]
-    return reduce(lambda a, b: a + b, map(lambda i: lefts[i] + mids[i] \
-                  + rights[i], range(7)))
-
-
-def rotate_marker_right((mrow, mcol), row, n):
-    if mrow != row:
-        return (mrow, mcol)
-    else:
-        return (mrow, (mcol + n) % 7)
-
-
-def rotate_marker_down((mrow, mcol), col, n):
-    if mcol != col:
-        return (mrow, mcol)
-    else:
-        return ((mrow + n) % 7, mcol)
-
-
-def derive_key(password):
-    i = 0
-    k = letters
-    for c in password:
-        (row, col) = find_ix(c)
-        k = rotate_down(rotate_right(k, i, col), i, row)
-        i = (i + 1) % 7
-    return k
-
-
-def encrypt(key, plaintext):
-    check_key(key)
-    mp = (0, 0)
-    ciphertext = ''
-    for p in plaintext:
-        pp = find_pos(key, p)
-        mix = find_ix(find_at_pos(key, mp))
-        cp = add_pos(pp, mix)
-        c = find_at_pos(key, cp)
-        ciphertext += c
-
-        key = rotate_right(key, pp[0], 1)
-        mp = rotate_marker_right(mp, pp[0], 1)
-        cp = find_pos(key, c)
-        key = rotate_down(key, cp[1], 1)
-        mp = rotate_marker_down(mp, cp[1], 1)
-        mp = add_pos(mp, find_ix(c))
-    return ciphertext
-
-
-def decrypt(key, ciphertext):
-    check_key(key)
-    mp = (0, 0)
-    plaintext = ''
-    for c in ciphertext:
-        cp = find_pos(key, c)
-        mix = find_ix(find_at_pos(key, mp))
-        pp = sub_pos(cp, mix)
-        p = find_at_pos(key, pp)
-        plaintext += p
-
-        key = rotate_right(key, pp[0], 1)
-        mp = rotate_marker_right(mp, pp[0], 1)
-        cp = find_pos(key, c)
-        key = rotate_down(key, cp[1], 1)
-        mp = rotate_marker_down(mp, cp[1], 1)
-        mp = add_pos(mp, find_ix(c))
-    return plaintext
-
-
-def encrypt_pad(key, plaintext, signature):
-
-    # TODO it would also be great to randomize the message length.
-
-    check_key(key)
-    padding = ''.join(map(lambda x: letters[random.randint(0,
-                      len(letters) - 1)], range(padding_size)))
-
-    return encrypt(key, padding + plaintext + '---' + signature)
-
-
-def decrypt_pad(key, ciphertext):
-    check_key(key)
-    return decrypt(key, ciphertext)[padding_size:]
-
-
-if __name__ == '__main__':
-
-    # a bit of test!
-
-    key = derive_key('s3cret_p4ssw0rd/31337')
-    print 'key:', key
-    enc = encrypt_pad(key, 'conflagrate_the_rose_bush_at_six!',
-                      'peace-vector-3')
-    print 'encrypted:', enc
-    dec = decrypt_pad(key, enc)
-    print 'decrypted:', dec