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Merge lsb and lsbset modules
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Flavien
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7 changed files with 48 additions and 120 deletions
256
stegano/lsb/generators.py
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256
stegano/lsb/generators.py
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#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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# Stegano - Stegano is a pure Python steganography module.
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# Copyright (C) 2010-2022 Cédric Bonhomme - https://www.cedricbonhomme.org
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#
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# For more information : https://git.sr.ht/~cedric/stegano
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>
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__author__ = "Cedric Bonhomme"
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__version__ = "$Revision: 0.3 $"
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__date__ = "$Date: 2011/12/28 $"
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__revision__ = "$Date: 2021/11/29 $"
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__license__ = "GPLv3"
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import itertools
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import cv2
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import numpy as np
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import math
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from typing import Dict, Iterator, List, Any
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def identity() -> Iterator[int]:
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"""f(x) = x"""
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n = 0
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while True:
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yield n
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n += 1
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def triangular_numbers() -> Iterator[int]:
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"""Triangular numbers: a(n) = C(n+1,2) = n(n+1)/2 = 0+1+2+...+n.
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http://oeis.org/A000217
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"""
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n = 0
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while True:
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yield (n * (n + 1)) // 2
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n += 1
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def fermat() -> Iterator[int]:
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"""Generate the n-th Fermat Number.
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https://oeis.org/A000215
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"""
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y = 3
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while True:
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yield y
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y = pow(y - 1, 2) + 1
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def mersenne() -> Iterator[int]:
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"""Generate 2^p - 1, where p is prime.
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https://oeis.org/A001348
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"""
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prime_numbers = eratosthenes()
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while True:
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yield 2 ** next(prime_numbers) - 1
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def eratosthenes() -> Iterator[int]:
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"""Generate the prime numbers with the sieve of Eratosthenes.
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https://oeis.org/A000040
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"""
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d = {} # type: Dict[int, List[int]]
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for i in itertools.count(2):
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if i in d:
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for j in d[i]:
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d[i + j] = d.get(i + j, []) + [j]
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del d[i]
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else:
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d[i * i] = [i]
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yield i
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def composite() -> Iterator[int]:
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"""Generate the composite numbers using the sieve of Eratosthenes.
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https://oeis.org/A002808
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"""
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p1 = 3
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for p2 in eratosthenes():
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for n in range(p1 + 1, p2):
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yield n
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p1 = p2
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def carmichael() -> Iterator[int]:
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"""Composite numbers n such that a^(n-1) == 1 (mod n) for every a coprime
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to n.
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https://oeis.org/A002997
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"""
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for m in composite():
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for a in range(2, m):
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if pow(a, m, m) != a:
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break
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else:
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yield m
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def ackermann_slow(m: int, n: int) -> int:
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"""Ackermann number."""
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if m == 0:
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return n + 1
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elif n == 0:
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return ackermann_slow(m - 1, 1)
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else:
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return ackermann_slow(m - 1, ackermann_slow(m, n - 1))
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def ackermann_naive(m: int) -> Iterator[int]:
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"""Naive Ackermann encapsulated in a generator."""
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n = 0
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while True:
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yield ackermann_slow(m, n)
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n += 1
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def ackermann_fast(m: int, n: int) -> int:
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"""Ackermann number."""
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while m >= 4:
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if n == 0:
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n = 1
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else:
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n = ackermann_fast(m, n - 1)
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m -= 1
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if m == 3:
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return (1 << n + 3) - 3
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elif m == 2:
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return (n << 1) + 3
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elif m == 1:
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return n + 2
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else:
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return n + 1
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def ackermann(m: int) -> Iterator[int]:
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"""Ackermann encapsulated in a generator."""
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n = 0
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while True:
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yield ackermann_fast(m, n)
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n += 1
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def fibonacci() -> Iterator[int]:
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"""Generate the sequence of Fibonacci.
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https://oeis.org/A000045
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"""
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a, b = 1, 2
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while True:
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yield a
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a, b = b, a + b
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def log_gen() -> Iterator[int]:
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"""Logarithmic generator."""
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y = 1
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while True:
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adder = max(1, math.pow(10, int(math.log10(y))))
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yield int(y)
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y = y + int(adder)
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polys = {
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2: [2, 1],
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3: [3, 1],
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4: [4, 1],
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5: [5, 2],
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6: [6, 1],
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7: [7, 1],
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8: [8, 4, 3, 2],
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9: [9, 4],
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10: [10, 3],
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11: [11, 2],
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12: [12, 6, 4, 1],
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13: [13, 4, 3, 1],
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14: [14, 8, 6, 1],
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15: [15, 1],
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16: [16, 12, 3, 1],
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17: [17, 3],
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18: [18, 7],
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19: [19, 5, 2, 1],
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20: [20, 3],
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21: [21, 2],
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22: [22, 1],
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23: [23, 5],
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24: [24, 7, 2, 1],
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25: [25, 3],
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26: [26, 6, 2, 1],
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27: [27, 5, 2, 1],
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28: [28, 3],
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29: [29, 2],
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30: [30, 23, 2, 1],
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31: [31, 3],
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}
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def LFSR(m: int) -> Iterator[int]:
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"""LFSR generator of the given size
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https://en.wikipedia.org/wiki/Linear-feedback_shift_register
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"""
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n: int = m.bit_length() - 1
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# Set initial state to {1 0 0 ... 0}
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state: List[int] = [0] * n
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state[0] = 1
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feedback: int = 0
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poly: List[int] = polys[n]
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while True:
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# Compute the feedback bit
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feedback = 0
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for i in range(len(poly)):
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feedback = feedback ^ state[poly[i] - 1]
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# Roll the registers
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state.pop()
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# Add the feedback bit
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state.insert(0, feedback)
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# Convert the registers to an int
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out = sum([e * (2**i) for i, e in enumerate(state)])
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yield out
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def shi_tomashi(
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image_path: str,
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max_corners: int = 100,
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quality: float = 0.01,
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min_distance: float = 10.0,
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) -> Iterator[int]:
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"""Shi-Tomachi corner generator of the given points
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https://docs.opencv.org/4.x/d4/d8c/tutorial_py_shi_tomasi.html
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"""
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image = cv2.imread(image_path)
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gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
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corners: np.ndarray = cv2.goodFeaturesToTrack(
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gray, max_corners, quality, min_distance
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)
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corners_int: np.ndarray[Any, np.dtype[np.signedinteger[Any]]] = np.array(
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np.int0(corners)
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)
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i = 0
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while True:
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x, y = corners_int[i].ravel()
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# Compute the pixel number with top left of image as origin
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# using coordinates of the corner.
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# (y * number of pixels a row) + pixels left in last row
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yield (y * image.shape[1]) + x
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i += 1
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64
stegano/lsb/lsb.py
Executable file → Normal file
64
stegano/lsb/lsb.py
Executable file → Normal file
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@ -20,55 +20,71 @@
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# along with this program. If not, see <http://www.gnu.org/licenses/>
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__author__ = "Cedric Bonhomme"
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__version__ = "$Revision: 0.4 $"
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__date__ = "$Date: 2016/08/04 $"
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__revision__ = "$Date: 2019/06/01 $"
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__version__ = "$Revision: 0.7 $"
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__date__ = "$Date: 2016/03/13 $"
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__revision__ = "$Date: 2019/05/31 $"
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__license__ = "GPLv3"
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from typing import IO, Union
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from typing import IO, Iterator, Union
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from .generators import identity
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from stegano import tools
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def hide(
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image: Union[str, IO[bytes]],
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message: str,
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encoding: str = "UTF-8",
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generator: Iterator[int] = None,
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shift: int = 0,
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encoding: str = "UTF-8",
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auto_convert_rgb: bool = False,
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):
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"""Hide a message (string) in an image with the
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LSB (Least Significant Bit) technique.
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"""
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hider = tools.Hider(image, message, encoding, auto_convert_rgb)
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width, height = hider.encoded_image.size
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width = hider.encoded_image.width
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for row in range(height):
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for col in range(width):
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if shift != 0:
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shift -= 1
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continue
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if not generator:
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generator = identity()
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if hider.encode_another_pixel():
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hider.encode_pixel((col, row))
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else:
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return hider.encoded_image
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while shift != 0:
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next(generator)
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shift -= 1
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while hider.encode_another_pixel():
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generated_number = next(generator)
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col = generated_number % width
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row = int(generated_number / width)
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hider.encode_pixel((col, row))
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return hider.encoded_image
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def reveal(
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encoded_image: Union[str, IO[bytes]],
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encoding: str = "UTF-8",
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generator: Iterator[int] = None,
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shift: int = 0,
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encoding: str = "UTF-8",
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):
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"""Find a message in an image (with the LSB technique)."""
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revealer = tools.Revealer(encoded_image, encoding)
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width, height = revealer.encoded_image.size
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width = revealer.encoded_image.width
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for row in range(height):
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for col in range(width):
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if shift != 0:
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shift -= 1
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continue
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if not generator:
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generator = identity()
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if revealer.decode_pixel((col, row)):
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return revealer.secret_message
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while shift != 0:
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next(generator)
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shift -= 1
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while True:
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generated_number = next(generator)
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col = generated_number % width
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row = int(generated_number / width)
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if revealer.decode_pixel((col, row)):
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return revealer.secret_message
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