Implementing AES Encryption: Best Practices and Step-by-Step Guide

Securing digital privacy and the information we share on the Internet is the main concern of the digital age we live in. One of the best ways to do that is by encrypting the online communication between the senders and recipients. Encryption does one thing that is indispensable; it turns the message into an unreadable mess that can only be deciphered with the encryption key. 

That might sound like a straightforward thing to do, but not all encryptions are at the same level just like not all passwords have the same level of security. Instead, there are various encryption algorithms. One of the most widely used is the Advanced Encryption Standard (AES), which is the main topic we’ll talk about. 

Known for its high level of security and effectiveness, AES is definitely a strong encryption algorithm, but its implementation takes detailed planning. If you want to learn more about it, jump onto the article where we’ll explain AES best practices and how to implement it step-by-step. 

What is AES Encryption? 

AES encryption algorithm is built on the term “symmetric encryption.” What that means is that both keys to encrypt and decrypt a piece of data are the same, increasing efficiency, simplifying the process, and being ideal for large amounts of data. In order to provide safe encryption, AES operates on fixed-size blocks of data, generally 128 bits, and applies numerous rounds of transformations.

This algorithm was first introduced by NIST and replaced the older Data Encryption Standard (DES). AES, the modern encryption algorithm supports three different key sizes; 128-bit, 192-bit, and 256-bit.

AES operates on periods which are called “rounds”, and makes the encryption stronger in every new round. The number of these rounds depends on the size of the encryption key. A bigger key definitively means better security, but 128-bit is usually sufficient for most applications. 

Best Practices for Implementing AES Encryption 

Securing the Encryption Keys

Encryption does a great job to ensure the privacy of the files sent over the Internet, as long as your encryption keys are secure. To secure AES encryption keys, use a reliable random number generator so that your keys are puzzling enough. If you have the means, go for bigger keys such as 192-bit and 256-bit. 

Make sure to store your keys in a secure place such as a hardware security module. Implement access restrictions to the physical and digital places where your keys are, and adopt strong authentication to prevent unauthorized access. 

Secure Key Exchange Protocols

Securely exchanging your keys is also essential when implementing AES encryption. Get to know reliable exchange protocols such as Diffie-Hellman and RSA. These will allow for a secure exchange of keys even over insecure networks. 

When establishing a shared secret key, make sure it happens in an authenticated and secure environment. Once your secret key is exchanged securely, it can then be used in an AES encryption. 

Data Integrity and Authentication

Use cryptography algorithms to ensure data integrity and authentication. Implement protocols such as HMAC (Hash-based Message Authentication Code) or CMAC (Cipher-based Message Authentication Code). MACs help you confirm data integrity by checking and verifying it. 

When choosing your MAC algorithm, make sure to prioritize your needs and the threat landscape. Consider factors such as key length, potential threats, and MAC performance. 

Protecting Against Side-Channel Attacks

During AES implementation, there might be some side-channel vulnerabilities (check out some examples here) that open the door to threats such as power analysis attacks and electromagnetic leakage. Make sure you know about these risks and are implementing the needed security measures. 

These measures would ideally include constant-time programming and randomizing memory access patterns, which prevent exposure when implementing AES encryption. 

Step-by-Step Guide to Implement AES Encryption

Choosing a Programming Language and AES Library

There is a variety of programming languages that support AES encryption. You need to select one that is compatible with AES, and the most popular choices here are Java, Python, C/C++, and .NET.

After selecting the language, you need to choose an AES library. All languages that support AES have cryptographic libraries, but to give some examples, you can use “javax.crypto” in Java, “cryptography” in Phyton. 

Installing and Configuring the AES Library

Find the library’s documentation or get support from its community to install the AES library properly. After you find out how to do it, adjust the configurations keeping in mind factors like encryption type (CBC, ECB), key size (128-bit, 192-bit, 256-bit), and padding scheme (e.g., PKCS7, ISO/IEC 7816-4).

Generating Cryptographic Key

As we mentioned previously, choose an effective and reliable number generator, possibly from the AES library, to create a robust key for the key size you choose. Remember, the bigger your key, the better the security. After you have the key, make sure to store it securely by adopting the practices we provided in the first section. 

Encrypting Data Using AES

To encrypt a piece of data through AES, you need to create blocks suitable for the encryption in accordance with your key size, such as 128-bit. Then, configure your parameters such as the encryption mode. 

Depending on the library and the language of your choice, apply AES encryption to each data block. Make sure to properly manage the IV for each block during decryption if a mode like CBC is being used. After that, decrypt the blocks and receive the plain text version of the data you encrypted. 

Handling Error Conditions and Exceptions

There might be errors on some blocks that might prevent you get the full data after decrypting the data. There are error-handling mechanisms you can apply to correct these mistakes and prevent issues in the encryption process. It is also possible to encounter issues such as incorrect keys, data corruption, or decryption failures. Implement proper measures beforehand to mitigate data loss or leakage. 

Conclusion

Encryption is a must for private communications made on the Internet due to the increasing number of online threats. While encrypting a piece of data sounds simple, there is much going on behind the scenes. Every encryption algorithm has its processes and security levels. 

One of the best ones out there is AES encryption, which is considered highly secure and efficient thanks to its symmetric key approach. By following the best practices in AES and implementing them properly, you can protect every piece of data with the maximum level of encryption with a straightforward process.