Add invisible-ink-mono to ch06

.gitignore

@@ -23,3 +23,4 @@ build/
 # Chapter 6
 output.docx
 LetterToUSDA.docx
+DearInternet.docx

docs/source/src.ch06.rst

@@ -4,6 +4,14 @@ src.ch06 package
 Submodules
 ----------
 
+src.ch06.c1\_invisible\_ink\_mono module
+----------------------------------------
+
+.. automodule:: src.ch06.c1_invisible_ink_mono
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
 src.ch06.p1\_invisible\_ink module
 ----------------------------------
 

src/ch06/c1_invisible_ink_mono.py

@@ -0,0 +1,179 @@
+"""Use stenography to hide messages in a word processor document.
+
+Use :py:obj:`docx.Document` to hide encrypted messages in a word processor
+document by embedding the encrypted message in a fake message's whitespace,
+then changing the encrypted message's font color to white.
+
+Note:
+    Using LibreOffice version 6.0.7.3
+
+Warning:
+    There are many ways this method of stenography can fail. Please don't use
+    for actual covert operations (covered in MIT License).
+
+"""
+from pathlib import Path, PurePath
+from platform import system
+
+import docx
+from docx.shared import RGBColor
+
+from src.ch06.p1_invisible_ink import get_text
+
+
+def check_fit(plaintext: list, ciphertext: list) -> int:
+    """Check if ciphertext can fit in plaintext's whitespace.
+
+    Sum number of blanks in **plaintext** and compare to number of characters
+    in **ciphertext** to see if it can fit.
+
+    Args:
+        plaintext (list): Paragraphs of a fake message in a list of strings
+            (likely from :func:`~src.ch06.p1_invisible_ink.get_text`).
+        ciphertext (list): Paragraphs of an encrypted message in a list of
+            strings (likely from :func:`~src.ch06.p1_invisible_ink.get_text`).
+
+    Returns:
+        Integer representing the number of needed blanks to fit
+        **ciphertext** in **plaintext**. ``0`` would mean that **ciphertext**
+        can fit in **plaintext**.
+
+    Note:
+        To separate words, the blanks in **ciphertext** count toward the
+        needed length of **plaintext**. By contrast, blank lines in
+        **plaintext** do not count.
+
+    """
+    blanks = sum(line.count(' ') for line in plaintext if line != '')
+    letters = sum(len(line) for line in ciphertext if line != '')
+    if blanks >= letters:
+        return 0
+    return letters - blanks
+
+
+def write_invisible(plaintext: list, ciphertext: list,
+                    template_path: str = None,
+                    filename: str = 'output.docx') -> None:
+    """Embed ciphertext in plaintext's letter whitespace.
+
+    Open a template file, **template_path**, with the needed fonts, styles,
+    and margins. Write each line in **plaintext** to the template file
+    and add each line in **ciphertext** to **plaintext**'s space between
+    letters by using a monospace font.
+    Save the new file as **filename**.
+
+    Args:
+        plaintext (list): Lines of a fake message in a list of strings
+            (likely from :func:`~src.ch06.p1_invisible_ink.get_text`).
+        ciphertext (list): Lines of an encrypted message in a list of
+            strings (likely from :func:`~src.ch06.p1_invisible_ink.get_text`).
+        template_path (str): Absolute path to .docx file with predefined
+            fonts, styles, and margins. Defaults to :py:obj:`None`. If not
+            provided, defaults will be created.
+        filename (str): File name to use for output file. Defaults to
+            ``output.docx``.
+
+    Returns:
+        :py:obj:`None`. **plaintext** is written to the file at
+        **template_path** with **ciphertext** embedded in the blank space.
+
+    Raises:
+        ValueError: If the number of spaces in **plaintext** aren't
+            enough to embed **ciphertext** based on output of
+            :func:`check_fit`.
+
+    Note:
+        As of python-docx v0.8.10, creating custom styles isn't well
+        supported. More info `here`_.
+
+        As a result, if a template isn't provided, the default template is
+        modified to use a font named ``Courier New`` on Windows and
+        ``Liberation Mono`` on other operating systems in the ``Normal``
+        style.
+
+    .. _here:
+        https://python-docx.readthedocs.io/en/latest/user/styles-understanding.html
+
+    """
+    blanks_needed = check_fit(plaintext, ciphertext)
+    if blanks_needed > 0:
+        raise ValueError(f'Need {blanks_needed} more spaces in the plaintext '
+                         f'(fake) message.')
+    if template_path is None:
+        # Modify default template.
+        doc = docx.Document()
+        style = doc.styles['Normal']
+        font = style.font
+        if system().lower().startswith('windows'):
+            font.name = 'Courier New'
+        else:
+            font.name = 'Liberation Mono'
+    else:
+        doc = docx.Document(template_path)
+
+    line_index, letter_index = 0, 0
+    for line in plaintext:
+        # Add new paragraph to template.
+        paragraph = doc.add_paragraph()
+        paragraph_index = len(doc.paragraphs) - 1
+        for letter in line:
+            # Add each letter to paragraph.
+            if all([letter == ' ',
+                    letter_index < len(ciphertext[line_index])]):
+                # Add real message to space and set color to white.
+                paragraph.add_run(ciphertext[line_index][letter_index])
+                run = doc.paragraphs[paragraph_index].runs[-1]
+                font = run.font
+                # Make red for testing.
+                font.color.rgb = RGBColor(255, 255, 255)
+                letter_index += 1
+            else:
+                paragraph.add_run(letter)
+            if all([letter_index >= len(ciphertext[line_index]),
+                    line_index < len(ciphertext) - 1]):
+                # Go to next line in ciphertext if end reached.
+                line_index += 1
+                letter_index = 0
+    doc.save(filename)
+
+
+def main(fakefile: str = None, cipherfile: str = None,
+         savepath: str = None) -> None:
+    """Demonstrate the invisible ink writer.
+
+    Demonstrate :func:`write_invisible`, but for testing,
+    it is a basic wrapper function for :func:`write_invisible`.
+    Embed **cipherfile** in **fakefile**'s whitespace.
+
+    Args:
+        fakefile (str): Path to .docx file with fake message.
+            Defaults to ``./c1files/fake.docx``.
+        cipherfile (str): Path to .docx file with real message.
+            Defaults to ``./c1files/real.docx``.
+        savepath (str): Path to .docx file for output.
+            Defaults to ``./c1files/DearInternet.docx``.
+
+    Returns:
+         :py:obj:`None`. The contents of **cipherfile**'s text is embedded
+         in **fakefile**'s whitespace and saved to **savepath**.
+
+    """
+    print('I can embed a hidden message in a .docx file\'s white space '
+          'between letters by making the font\ncolor white. It\'s far less '
+          'bulletproof than it sounds.\n')
+    current_dir = Path('./c1files').resolve()
+    if fakefile is None or cipherfile is None:
+        fakefile = PurePath(current_dir).joinpath('fake.docx')
+        cipherfile = PurePath(current_dir).joinpath('real.docx')
+    if savepath is None:
+        savepath = PurePath(current_dir).joinpath('DearInternet.docx')
+    faketext = get_text(fakefile, False)
+    ciphertext = get_text(cipherfile)
+    write_invisible(faketext, ciphertext, None, savepath)
+    print('Fin.\n')
+    print('To read the hidden message, select the entire document and\n'
+          'highlight it a darkish gray.')
+
+
+if __name__ == '__main__':
+    main()

tests/data/ch06/constants.py

@@ -0,0 +1,111 @@
+"""Test Chapter 6 Constants.
+
+Constants for test_chapter06.py.
+
+Attributes:
+    GET_TEST (list): List of strings with expected output of
+        tests.test_chapter06.TestInvisibleInk.test_get_text test values.
+    WRITE_DEFAULT_MONO (list): List of strings with expected output of
+        src.ch06.c1_invisible_ink_mono.write_invisible default values.
+    WRITE_TEST_MONO (list): List of strings with expected output of
+        tests.test_chapter06.TestInvisibleInkMono.test_write_invisible test
+        values.
+    MAIN_TEST_MONO (list): List of strings with expected output of
+        tests.test_chapter06.TestInvisibleInkMono.test_main test values.
+    MAIN_DEFAULT_MONO (list): List of strings with expected output of
+        src.ch06.c1_invisible_ink_mono.main default values.
+
+"""
+GET_TEST = [
+    'This is a test document.',
+    'This is a paragraph with two runs. However, it’s not because it has two '
+    'lines.',
+    'There is intentionally a lot of blank spaces to check if the code can count '
+    'them correctly.',
+    'So, don’t send me e-mails saying that the formatting in my test files is '
+    'incorrect.',
+    'Word.']
+
+WRITE_DEFAULT_MONO = [
+    'ThisTishaitestsdocument withiaslot ofsfiller,'
+    'uorpunnecessarypwordiness.',
+    'Please,otrysnotetodwrite liketthisobecause itbiseas annoyingaas '
+    'itsishunnecessary.',
+    'Unless,oofrcourse,tyou,are '
+    'writinguantypeeofncharactercthatrisywordypandtusesewordsd'
+    'unnecessarily.',
+    'In thatmrare,euncommonsinstance,sitaisgperfectlyepermissible.'
+    'to be wordy.']
+
+WRITE_TEST_MONO = [
+    'ThisTishaitestsdocument withiaslot ofsfiller,'
+    'uorpunnecessarypwordiness.',
+    'Please,otrysnotetodwrite liketthisobecause itbiseas annoyingaas '
+    'itsishunnecessary.',
+    'Unless,oofrcourse,tyou,are '
+    'writinguantypeeofncharactercthatrisywordypandtusesewordsd'
+    'unnecessarily.',
+    'In thatmrare,euncommonsinstance,sitaisgperfectlyepermissible.'
+    'toHbeiwordy.']
+
+MAIN_TEST_MONO = [
+    'ThisTishaitestsdocument withiaslot ofsfiller,uorpunnecessarypwordiness.',
+    'Please,otrysnotetodwrite liketthisobecause itbiseas annoyingaas '
+    'itsishunnecessary.',
+    'Unless,oofrcourse,tyou,are '
+    'writinguantypeeofncharactercthatrisywordypandtusesewordsdunnecessarily.',
+    'In thatmrare,euncommonsinstance,sitaisgperfectlyepermissible.to be wordy.']
+
+MAIN_DEFAULT_MONO = [
+    'DearYInternet,',
+    'Schoolotaughtumerthat yourstartedeoutaaslARPANET: '
+    'twoncomputerasystemsm(specifically,eUCLA’s NetworkiMeasurementsCenter '
+    'andaSRI’s '
+    'NLSpsystem)oconnectedrtogethertwaymbackaonnOctobert29,e1969.aIurecently '
+    'learnedothefTCP/IP '
+    'standardiwasn’tnadoptedtuntileMarchr1982candothatnaccessntoethecTCP/IPtnetworkewasn’tdexpanded '
+    'untiln1986ewhentthewNSFoprovidedraccesskfor.researchers '
+    'toYconnectotousupercomputer sitesainrtheeUnited Statesaat '
+    'thenblazingespeedtofw56okbit/s.\n'
+    '\n'
+    'Surprisingly,rcommercialkISPs didn’tocomefaround '
+    'untilntheelatet1980swandoearlyr1990s,katswhich '
+    'pointtthehARPANETawastdecommissioned.',
+    'I remembercinothenearlys1990sithatsusingtascomputer tooinstantfmessage '
+    'someoneponrtheiothervsideaofttheeworld,was '
+    'apbigudealbbecauselthatiwascas,close '
+    'toarealctimeaasdpossibleewithoutmrackingiupca,major '
+    'longbdistanceubillsonithenlandline.eAlthough,sIsam,curious '
+    'whatathenlatencydwas backgthen…',
+    'Theseodays,vyouearerprovidingnusmaewayntotwirelessly '
+    'usenpocketecomputersttowcheckoinrtokoursfavorite coffeeoshop,fstream '
+    'musiclandovideocwhilealaughinglat danktmemesoon '
+    'socialgmedia,landopaybouratablwith astapcusingoourpvirtualewallet.',
+    'You,connect solmanyicomputersntogetherkthateadnew IPbprotocolyhad toaget '
+    'standardizedbtorsupportothemaalldas theyacontinuertorgrowainynumber. '
+    'Everythingofromfa '
+    'whiteepaperlonecuttingcedgetresearchrtooannoldiblogcabout,cats '
+    'havewtheiriownrIPeaddress.lNotetosmentionsall,the peopleaconnectingntodread '
+    'moreoaboutpthem.',
+    'Inttheifuture,cweawillllikely '
+    'expectnmoreefromtyouwasoanrincreasingknumberiofnInternetgusers '
+    'expecttwirelessenetworksctohhandlenasomuchltrafficoasgbroadbandinetworkseandsas.laptops '
+    'andBdesktopsyare eithertrelegatedhtoegaming orwofficeawork.\n'
+    '\n'
+    'Perhapsywe,will relyIon youaevenmmore '
+    'astcompaniesrforgouconventionalldesktopsyand, '
+    'instead,soptuforrthinpclientsrmadeiofsaegraphicsdcard andbEthernetycard '
+    'withhmultipleoscreenswthat connectmtouaccloudhserver '
+    'instancetthateinstantiatesxonlyton userflogin,ithentloadssuser '
+    'settingsiandnworkspaces fromtahcentralizedaserver.tThen, '
+    'whenftheauserkisedone, saveslinstanceedatatbackttoethercentralized.server '
+    'andMthenadeactivatesytobsaveeresources.',
+    'Some systemsIalready implementsyouhusingolightuoutlindthe '
+    'openhairabecausevdataeis transmittedtfasterothatnway.eIndaddition '
+    'toithethuge bundlesdofocablewthatnstretch acrossathe '
+    'oceanbflooritotconnect?both sidesNofathehworld,together.',
+    'I lookeforwardxtocwhateyouswillsbecomeiinvtheefuturen–eevensifsit '
+    'isidangerous,shigh-powered lasergbeamsoandoevenddanker.memes.',
+    'Sincerely,',
+    'Jose',
+    'Works consulted: https://en.wikipedia.org/wiki/Internet']

tests/data/ch06/main/invisible_ink_mono.txt

@@ -0,0 +1,7 @@
+I can embed a hidden message in a .docx file's white space between letters by making the font
+color white. It's far less bulletproof than it sounds.
+
+Fin.
+
+To read the hidden message, select the entire document and
+highlight it a darkish gray.