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Basic Cryptography Concepts and Security Weakness in Software

If you are a software engineer, you must have proper knowledge of the software security aspect. But the thing is, with the competitive and fast-paced environment of the software development lifecycle, you may under huge pressure to deliver the business requirements without paying too much attention to the security breaches of your software. But if you have proper knowledge in software security aspect you obviously know how to develop software without any security weaknesses and if there any, you will know how to deal with those.

So, in the first section of this article, I will explain some common software security weaknesses that you should be aware of as a software engineer.


I know everyone who’s going to read this article already familiar with bugs, and you may already guess that it would be included in this article as a security weakness. Bugs are a very common source of software security defects. Unfortunately, most of the software contains some form of bugs within them. These can be some minor bugs that show the wrong label for the wrong field, or these can be very critical bugs that impacting the user’s ability to log in or even leading to a complete system failure.

Also, your software may have some bugs that represent security vulnerabilities that may result in an information leak or unauthorized access. So, hackers can easily use these types of bugs to harm your software.

Broken Authentication

Authentication is basically a process of identifying someone whom they are claimed to be. Software with incorrectly configured user and session authentication poses great vulnerability. As an example, when functions related to the authentication process unable to do the validation properly, security issues will emerge. So, hackers can take advantage of broken authentication to get users’ passwords or session tokens, or even take over users’ accounts to assume their identity.

Sensitive Data Exposure

Some software including web and mobile applications do not provide necessary protection for sensitive data such as financial information, health information, and other critical data like passwords and usernames. So, it makes this information available to hackers. Now they could use this information to do fraud, steal people’s identities, and conduct other crimes. These sensitive data require extra protection such as encryption to protect them from hackers and unauthorized access.


There are several injection vulnerabilities like SQL, OS, and LDAP that take place when untrusted data is sent to an interpreter as a command. This untrusted data tricks the interpreter into accessing data without the right authorization or performing unintended commands. Among these, SQL injection is one of the most used web hacking techniques among attackers. SQL injection makes it possible to execute malicious SQL statements with the intent of exploiting information in a database. So, the hackers can gain access to sensitive data stored in the database.

Broken access control

Can you imagine what happens if, all authenticated users get access to all information in the system? They can update data, delete data, access other users’ accounts, and view sensitive data. Also, Users would make modifications according to their needs while accessing authorized sensitive data.

These things happen when a software lacks proper configuration or missing restrictions on what users can access and what they can’t. Above all, hackers always target such flaws to access information in the system while modifying access rights and user data.


These days, millions of people are deeply associated with applications and computing systems to fulfill their day-to-day tasks. So, if we develop software, we should be responsible to secure all the information and data of the users who use that software. This is where Cryptography comes to save the day. Cryptography is the method of transmitting secured data and communications via few codes so that only the destined person knows about the actual information that is transmitted. This form of process stops unauthorized accessibility for the data.

Encoding of information in cryptography follows mathematical theories and calculations known as algorithms. The encoded data is transmitted because it makes it difficult to find the original data. These sets of rules are utilized in the procedures of digital signing, authentication to secure data, and secure all your financial transactions. There are 4 core objectives in cryptography:

  • Privacy — The transmitted data should not be known by external parties except for the intended individual.
  • Reliability — the data cannot be modified in storage or transfer between the sender and the destined receiver.
  • Non-repudiation — Once the data is transmitted, the sender has no chance to deny it later.
  • Authentication — Both the sender and receiver need to be verified who they claim to be.

In cryptography, encryption of the information can be classified into three types.

1) Symmetric Key Cryptography

This is also called Private or Secret key cryptography. Here, both the information receiver and the sender make use of a single key to encrypt and decrypt the message. The frequent kind of cryptography used in this method is AES (Advanced Encryption System). The approaches implemented through this type are way quicker. Few types of Symmetric key cryptography are:

  • Block
  • Block cipher
  • DES (Data Encryption System)
  • RC2
  • IDEA
  • Blowfish
  • Stream cipher

2) Asymmetric Key Cryptography

This is also called Public-key cryptography. It follows a diverse and protected method in the transmission of information. By using a couple of keys, both the sender and receiver go with encryption and decryption processes. A private key is stored with each person and the public key is shared across the network so that a message can be transmitted through public keys. The frequent kind of cryptography used in this method is RSA.

The public key method is more secure than that of a private key.

A few of the kinds of Asymmetric key cryptography are:

  • RSA
  • DSA
  • PKCs
  • Elliptic curve techniques

3) Hash Function

Taking the random length of the message as input and delivering a fixed length of the output is the algorithm followed by a hash function. It is also termed as a mathematical equation by taking numerical values as input and produce the hash message. This method will not need any kind of key as it functions in a one-way scenario.

There are various rounds of hashing operations and every round considers input as an array of the recent block and generates last round activity as output. A few of the functionalities of the hash are:

  • Message Digest 5 (MD5)
  • Whirlpool
  • SHA (Secure hash Algorithm)

Cryptography Tools

Cryptography tools are very useful in the situations of signature confirmation, code signing, and performing other cryptography activities. So, in this chapter, I will explain the most commonly used cryptography tools.

Security Token

This token is utilized to verify the user. A security token is supposed to be encrypted to perform a protected exchange of information. Also, it provides complete state-fullness for the HTTP protocol. So, the server-side formulated token is utilized by a browser to go on with the state. Basically, it is the method that moves with remote authentication.


This is the tool used to authorize the encryption process. This tool is also called a Java cryptographic library. These Java libraries are included with predefined activities where those need to be imported before implementation.


The information maintained in the docker is completely in an encrypted format. In this, cryptography has to be strictly followed to move with encryption of data. Furthermore, both files and information are encrypted, therefore allowing no one to access the things having no exact access key. Docker is also known as cloud storage allowing users to manage the information either on a dedicated or shared server.


This tool is mostly used by Microsoft to sign the files. Adding a signature and time stamp to any kind of file is the most important feature supported by this tool. With the timestamp in the file, it holds the ability to authenticate the file. The whole feature in SignTool.exe ensures for augmented reliability of the file.



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Nisal Pubudu

Nisal Pubudu

Associate Software Engineer at Virtusa