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Style Guide

The following rules are meant to ensure consistency of the MASTG:

  1. Keep the content factual, brief and focused. Avoid duplicating other sections of the guide;
  2. Refrain from advertising commercial tools or services;
  3. When giving technical instructions, address the reader in the second person.

We recommend you to take these free Google courses when writing or reviewing content for the MAS project:

1. How to Write Content

Amount of Content

The primary measure for amount of content on a page should be based on the purpose it serves.

  • Use short pages

Those containing one or two screens of text at most. Users are scanning for link choices. Use longer pages (those that require more scrolling or reading) deeper within the chapter where content can be printed and read later.

  • For very large sections of information

Consider creating a supporting document and linking to it from the page rather than displaying all the information directly on the page.

Gender Neutrality

The MASTG reaches all kind of people all over the world. To ensure inclusiveness and diversity, please refrain from using the following throughout the book:

  • she / her / hers / herself
  • he / him / his / himself

Or any other constructions like "he/she", "s/he", "his or her". Instead, use the following gender-neutral alternatives:

  • Omit the pronoun if possible: "The user authenticates himself using ..." -> "The user authenticates using ..."
  • Replace pronouns with "the or "a": "When the user enters his password ..." -> "When the user enters the password ..."
  • Use plural nouns and pronouns: "An attacker will use his jailbroken device ..." -> "Attackers will use their jailbroken devices ..."
  • Use the second person: "If the attacker runs this code, he can bypass ..." -> "If you run this code, you can bypass ..."
  • Use the imperative: "A developer should never use ... in his code" -> "Never use ... in your code!"

There is one exception: We are still using "man in the middle", as it is simply a common term in the industry and there is no common replacement for it.

Timeliness of Content

Keeping accurate and timely content establishes the OWASP MAS deliverables as a credible and trustworthy source of information.

When using statistical data on your page, ensure that the information is current and up-to-date and is accompanied by the source from which it was derived, along with the date the data was compiled.

Content for the Digital Platform Versus for Print

Write concise content that the user can read quickly and efficiently. For digital content - create shorter pages that are cross-linked. If your content is likely to be printed, create one long page.


Write for an international audience with a basic level of technical understanding i.e. they have a mobile phone and know how to install an app. Avoid hard-to-translate slang words/phrases to ensure content is accessible to readers who aren't native English speakers.

Context and Orientation

Let the users know where they are on every page. Establish the topic by using a unique page heading.

Include a clear and concise introduction where possible.

Link to background information where necessary.

Write so People Will Read with Joy

Use the following methods to increase scannability:

  • Use left alignment for headings, subheadings, and text
  • Link where appropriate
  • Use lists rather than paragraphs wherever possible
  • Use dashes - rather than asterisks * for lists
  • Include only one main idea in each paragraph
  • Put the most important information at the top
  • Start the page with the conclusion as well as a short summary of the remaining content
  • Use headings where applicable
  • Use short, simple words that are to the point
  • Be concise and focused

For longer pages, use the following tools to make the page easily scannable:

  • Anchor links
  • Subheadings and relevant links
  • Bulleted copy
  • Meaningful graphics, or pull quotes, to break up larger blocks of text
  • End links

Effective Use of Lists

When presenting your content in a list format:

  • Use numbered lists when the order of entries is important.
  • Use bulleted lists whenever the order of the entries is not important.
  • Generally, limit the number of items in a single list to no more than nine.
  • Generally, limit lists to no more than two levels: primary and secondary.
  • Punctuate and capitalize list items consistently (CMOS 6.124-6.126).
  • Don't add end punctuation to list items that are not complete sentences unless they complete the sentence that introduces the list.
  • Use appropriate capitalization and end punctuation for list items that individually form complete sentences.
  • If the list items complete an introductory sentence, end each (except the last item) with a comma and do not add "and" after the second-to-last item. End the last item with appropriate end punctuation (usu. a period).

Numbering Conventions

When using a number between zero and ten, spell out the number (e.g., "three" or "ten").

When using any number higher than ten, use the numeric version (e.g., "12" or "300").

2. Language

American Spelling and Terminology

Use American spelling and terminology.

Change all British spelling and terminology to the American equivalents where applicable. This includes "toward" (US) vs. "towards" (UK), "among" (US) vs. "amongst" (UK), "analyze" (US) vs. "analyse" (UK), "behavior" (US) vs "behaviour" (UK), etc.


Adhere to standard grammar and punctuation rules when it comes to pluralization of typical words.

The plural of calendar years does not take the apostrophe before the "s". For example, the plural form of 1990 is 1990s.

Title Capitalization

We follow the title case rules from the "Chicago Manual of Style":

  • Capitalize the first and last word in a title, regardless of part of speech
  • Capitalize all nouns (app, encryption, package), pronouns (you, she, it), verbs (analyze, compile, inspect), adjectives (active, insecure, weak), adverbs (immediately, quietly), and subordinating conjunctions (as, because, although)
  • Lowercase "to" as part of an infinitive
  • Lowercase all articles (a, the), prepositions (to, at, in, with), and coordinating conjunctions (and, but, or)

When in doubt, you can verify proper capitalization on


This is a list of words/abbreviations that are used inconsistently at the moment in the MASTG and need standardization:

  • man-in-the-middle attack (MITM)


Use the following common contractions:

  • are not -> aren't
  • cannot -> can't
  • could not -> couldn't
  • did not -> didn't
  • do not -> don't
  • does not -> doesn't
  • has not -> hasn't
  • had not -> hadn't
  • have not -> haven't
  • is not -> isn't
  • it is -> it's
  • that is -> that's
  • there is -> there's
  • was not -> wasn't
  • were not -> weren't
  • will not -> won't
  • would not -> wouldn't
  • you are -> you're
  • you have + verb -> you've + verb
  • you will -> you'll


Abbreviations include acronyms, initialisms, shortened words, and contractions.

  • Spell out the term the first time it's used, followed by the abbreviation in parentheses. Example: OWASP Mobile Application Security Testing Guide (MASTG). Subsequent usages in the same chapter may include the abbreviation only.
  • If it only appears once in the content, spell out the term instead of using the abbreviation.
  • In titles and headings, use the abbreviation but be sure to properly introduce it (see above) in the text that follows.
  • Use "a" or "an" depending on the pronunciation of the acronym. Example: a DLL, an APK, a URL, a SQL.
  • Add an "s" for the plural form unless the abbreviation already stands for a plural noun. Example: the APIs, CSS (not CSSs).
  • If the abbreviation is better known as its full spelled-out term, use only the abbreviation. Example: PDF, URL, USB, ZIP.

The following snippet demonstrates most of these points:

## JAR Files

JAR (Java ARchive) files are [...]

APKs are packed using the ZIP format. An APK is a variation of a JAR file [...]

For commonly used file formats such as APK, IPA or ZIP, please do not refer to them as ".apk", ".ipa" or ".zip" unless you're explicitly referring to the file extension.

Referencing Android versions

Use the following format when referring to an Android version: Android X (API level YY). Usage of the descriptive name (Ex: Oreo) is discouraged.

Ex: Android 9 (API level 28)

Addressing the Reader in Test Cases

Throughout the guide, you may want to address the readers in order to tell them what to do, or what they should notice. For any such case, use an active approach and simply address the reader using "you".

Correct: If you open the AndroidManifest.xml file, you will see a main Application tag, with the following attributes: atr1, atr2 and atr3. If you run the following command, you will see that atr1 is actually dangerous: [...].

Wrong: The AndroidManifest.xml file contains an Application tag, with the following attributes: atr1, atr2 and atr3. The command below shows that atr1 is dangerous: [...].

Wrong: If we open the AndroidManifest.xml file, we will see a main Application tag, with the following attributes: atr1, atr2 and atr3. If we run the following command, we will see that atr1 is actually dangerous: [...].

3. External References

Use markdown's in-line link format (A) [TEXT](URL "TITLE") or (B) [TEXT](URL).

For example:

The [threat modeling guidelines defined by OWASP]( "OWASP Threat Modeling") are generally applicable to mobile apps.

When using (A), be sure to escape special characters such as apostrophe (\') or single quote (`), as otherwise the link will be broken in Gitbook.

Wrong usage, see "iPhone's":

[UDID of your iOS device via iTunes]( "How to Find Your iPhone's UDID")

Right usage, see "iPhone\'s":

[UDID of your iOS device via iTunes]( "How to Find Your iPhone\'s UDID")

When adding links to the "References" section at the end of the chapters use - Title - <url>. This is needed to force latex to print URLs properly for the PDF.

For example:

- adb - <>

Books and Papers

For books and papers, use the following format: [#NAME].

And include the full reference in the "References" section at the end of the markdown file manually. Example:

An obfuscated encryption algorithm can generate its key (or part of the key)
using data collected from the environment [#riordan].

And under the "References" section at the end of the chapters:

- [#riordan] -  James Riordan, Bruce Schneier. Environmental Key Generation towards Clueless Agents. Mobile Agents and Security, Springer Verlag, 1998


The general form for citing technical reports is to place the name and location of the company or institution after the author and title and to give the report number and date at the end of the reference.

Basic Format:

- [shortname] J. K. Author, "Title of report," Abbrev. Name of Co., City of Co., Abbrev. State, Rep. xxx, year

- [shortname] \[Author(s)\], \[Title\] - Link


- [shortname] \[Author(s)\], \[Title\], \[Published\], \[Year\]

- [examplebook] J. K. Author, "Title of chapter in the book," in Title of His Published Book, xth ed. City of Publisher, Country if not USA: Abbrev. of Publisher, year, ch. x, sec. x, pp. xxx-xxx.

NOTE: Use et al. when three or more names are given


- [klaus] B. Klaus and P. Horn, Robot Vision. Cambridge, MA: MIT Press, 1986.
- [stein] L. Stein, "Random patterns," in Computers and You, J. S. Brake, Ed. New York: Wiley, 1994, pp. 55-70.
- [myer] R. L. Myer, "Parametric oscillators and nonlinear materials," in Nonlinear Optics, vol. 4, P. G. Harper and B. S. Wherret, Eds. San Francisco, CA: Academic, 1977, pp. 47-160.
- [abramowitz] M. Abramowitz and I. A. Stegun, Eds., Handbook of Mathematical Functions (Applied Mathematics Series 55). Washington, DC: NBS, 1964, pp. 32-33.

4. References Within The Guide

For references to other chapters in the MASTG, simply name the chapter, e.g.: See also the chapter "Basic Security Testing", See the section "Apktool" in the chapter "Basic Security Testing" etc. The MASTG should be convenient to read as a printed book, so use internal references sparingly. Alternatively you can create a link for the specific section:

See the section "[App Bundles](" in the chapter ...

Note that in such a case the anchor (everything after the #) should be lowercase, and spaces should be replaced with hyphens.

5. Insert Pictures

Pictures should be uploaded to the Images/Chapters directory. Afterwards they should be embedded by using the image tag, a width of 500px should be specified. For example:

<img src="Images/Chapters/0x06d/key_hierarchy_apple.jpg" width="500px"/>
- *iOS Data Protection Key Hierarchy*

6. Punctuation Conventions

Lowercase or Capital Letter after a Colon

Chicago Manual of Style (6.61: Lowercase or capital letter after a colon) says: lowercase the first word unless it is a proper noun or the start of at least two complete sentences or a direct question.

Serial Comma Use

Use a serial comma before "and" for the last item in a run-in list of three or more items. For example:

We bought apples, oranges, and tomatoes from the store.

Quote Marks and Apostrophes

Use straight double quotes, straight single quotes, and straight apostrophes (not curly quotes/apostrophes).

Technical Terms

Spell/punctuate specific technical terms as they are used by the company (e.g., use the company website).

In order of preference, spell/punctuate generic technical terms according to

  1. Merriam Webster's Collegiate Dictionary, 11th edition.
  2. Microsoft Manual of Style, 4th edition
  3. (Free Online Dictionary of Computing)
Noun Form Adjectival Form
App Store NA
backend backend
Base64 Base64-
black box same
Bundle ID NA
bytecode NA
client side client-side
codebase same
code signing same
command line same
disassembler NA
end users NA
file name same
macOS NA
pentest same
PhoneGap NA
Python NA
repackage NA
runtime same
server side server-side
snapshot length NA
use case same
Wi-Fi same
white box same


Markdown blockquotes can be used for comments in the documents by using >

> This is a blockquote

8. Code and Shell Commands

Use code blocks when including sample code, shell commands, and paths. In Markdown, code blocks are denoted by triple backticks (```). GitHub also supports syntax highlighting for a variety of languages. For example, a Java code block should be annotated as follows:

    public static void main(String[] args) { System.out.println(" Hello World!"); } } ;

This produces the following result:

public static void main(String[] args) { System.out.println(" Hello World!"); } }

When including shell commands, make sure to the language for correct syntax highlighting (e.g. shell or bash) and remove any host names and usernames from the command prompt, e.g.:

    $ echo 'Hello World'
    Hello World

When a command requires parameters that need to be modified by the reader, surround them with angle brackets:

$ adb pull <remote_file> <target_destination>

In-text Keywords

When they do not occur in a code block, place the following code-related keywords in backticks (``), double straight quote marks (""), or leave unpunctuated according to the table:

Backticks Quotation Marks No Punctuation
function names section titles application name
method names chapter titles folder names
commands book titles memory addresses (e.g. 0x100044520)
class names flags values (e.g., "true", lowercase)
block names command options (e.g., "help" option)
flag names single menu item (e.g., "Home" menu)
file names system error msgs.
package names
file paths
port numbers
binary names
method/function arguments
method/function argument or return values (e.g., true, 0, YES)
XML attributes (e.g., get-task-allow on iOS Plists, "@string/app_name" on Android Manifests)
XML attribute values (e.g., android:label on Android Manifests)
property names
object names
API calls
interface names

If nouns in backticks are plural, place the "s" after the second backtick (e.g. RuntimeExceptions). Do not add parentheses, brackets, or other punctuation to any keywords that are in backticks (e.g., main not main()).

When referring to any UI element by name, put its name in boldface, using **<name>** (e.g., Home -> Menu).