To get the most out of this book

Although this book builds a foundation of knowledge about cryptography and peer-to-peer networking concepts, hands-on Python programming experience and theoretical networking knowledge would be an advantage.

Most of the applications used in this book can be executed on any platform, the examples shown are executed using Ubuntu 16.04.5 LTS.

You should be comfortable with installing applications with the help of package management tools such as APT on Ubuntu or equivalent tools on Mac or Windows.

Since most of the application source code is hosted on GitHub, you should be familiar with the Git version control system.

Download the example code files

You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packt.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Foundations-of-Blockchain. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://www.packtpub.com/sites/default/files/downloads/9781789139396_ColorImages.pdf.

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Mount the downloaded WebStorm-10*.dmg disk image file as another disk in your system."

A block of code is set as follows:

from Crypto.Hash import SHA256
 
hash_object = SHA256.new(data=b'First')
print(hash_object.hexdigest())

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

from Crypto.Hash import SHA256
 
hash_object = SHA256.new(data=b'First')
print(hash_object.hexdigest())

Any command-line input or output is written as follows:

$  curl -X POST http://localhost:10332 -H 'Content-Type: application/json' -d '{ "jsonrpc": "2.0", "id": 5, "method": "getversion", "params": [] }'

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "A different header is created by altering a variable field called nonce in the header."

Warnings or important notes appear like this.

Tips and tricks appear like this.