Discover how to manipulate PDFs using Python. Gain hands-on experience with real-life scenarios and broaden your knowledge in handling and processing PDF files efficiently.

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mypdftoolbox.tar.gz

pdf_compare

pdf_did_metadata

pdf_xmp_metadata

pdf_compute_checksum

pdf_merger

pdf_pages_splitter

pdf_pages_rotator

pdf_pages_remover

pdf_pages_shuffler

pdf_pages_watermarker

pdf_convert2img

pdf_extract_tables

pdf_extract_images

pdf_extract_links

pdf_annotator

pdf_redactor

pdf_parser

pdf_convert2docx

pdf_convert2pptx

pdf_compress

pdf_secure

pdf_crack

pdf_create

pdf_sign

pdf_scan

pdf_comment

pdf_compare_files

pdf_attach

pdf_extract_attachments

pdf_embed_js

pdf_change_rights

This course will provide you with hands-on experience in PDF manipulation using the Python programming language. It integrates the most common real-life scenarios into its proceedings and supplies you with a framework of "how to do it". 

This course is addressed to Python programmers who seek to broaden their knowledge in the Python programming language. Moreover, it targets those who are eager to gain in-depth experience in handling and processing PDF files which constitute a large part of our day-to-day lives.

PDF Management in Python

# Introduction ##

Tons of data are being sent over the Internet or other local networks. This data is susceptible to data loss due to network issues or even malicious attacks. 

Typically, a checksum is used to ensure that the data received is unharmed and free of errors and losses.

# Checksum stands for what ##

A **checksum** is the result of running an algorithm, called a ***cryptographic hash function***, on a block of information, standardly a single file. Matching the checksum generated using a specific version of a file, with the one furnished by the original source of the file, confirms that the designated file version is genuine and untampered.

A checksum may have different names. It is commonly called a hash sum, while less common names include hash value, hash code, or simply a hash.

A checksum value by itself is intrinsically a string of letter characters and numbers that act as a sort of fingerprint for a string, a file, or a set of files.

# Common reasons for inconsistent checksums ##

Multiple factors might lead to mismatches in checksum values such as:

* ### Malicious tampering ###
The difference between the stored value and the computed value of the checksum of a certain file denotes that one of them was modified, but this does not ascertain which of them is legitimate.
Identical files will have the same checksum. Changing anything other than the file name will result in a different checksum.
In fact, the checksum technique helps detect integrity violations. 

* ### Data corruption ###
Data corruption doesn’t automatically mean that the data is malicious. Files might be inadvertently altered or modified during a file transfer if they include an unexpected type of encoding.

* ### Incompatibility in hashing algorithms ###
Any dissimilarity in hashing algorithms leads to different checksums.

# The checksum algorithms ##
At the core of a checksum, there is a software algorithm used to create the checksum value. 
The main purpose of an algorithm is to assign a numerical value to a file. This value is based on the content and the size of a file.

There is a wide array of checksum algorithms, which include:

|  Algorithm | Checksum Size  |
|:-| - |:-|
| MD5 | 32 |
| SHA1 | 40 |
| SHA256 | 256 |
| SHA384 | 96 |
| SHA512 | 128 |

These algorithms listed per order of their security strengths, from lower to higher, differ mainly based on the security strengths they provide for the data being hashed. The security strength refers to the amount of work, that is, the number of operations, that are required to break a cryptographic algorithm.

# Scope ##
 
This lesson aims to show us how to compute a checksum value for a PDF file using a lightweight command-line-based utility developed in the Python programming language. 

# Pre-requisites ##

As our requirements stand, the following component comes into play:

**Hashlib** is an interface for hashing messages easily. This built-in module will allow the usage of different hash algorithms in the Python Programming Language.
	
## Let’s head into coding ###

Within the code snippet below, we will perform the following steps:
 1. Import the libraries (**Line 1**).
 2. Set a read buffer size (**Line 4**).
 3. Define a function called `verify_algorithm` tto check that the algorithm specified by the user is part of the list of algorithms defined in the module. If not, then this list is displayed on the console (**Lines 10-12**).

Learn to compute the checksum of a PDF file using various hashing algorithms.

Computing the Checksum of a PDF File

Introduction

PDF Management Core Functions

Pages Processing

Content Processing

Document Processing

Conclusion

Appendices

Computing the Checksum of a PDF File

Introduction

Checksum stands for what

Common reasons for inconsistent checksums