An FIPS-approved cryptographic technique that can be used for securing electronic data is specified by the Advanced Encryption Standard (AES). Information can be encrypted and decrypted with the symmetric block cipher method known as the AES algorithm. Data that has been encrypted is transformed into ciphertext, an unreadable form; data that has been decrypted is returned to plaintext, the original form. Data can be encrypted and decrypted in blocks of 128 bits using the AES method with cryptographic keys of 128, 192, and 256 bits.

How AES encryption works?

Three block ciphers, or cryptographic keys, are part of AES −

• AES-128 encrypts and decrypts message blocks using keys of a length of 128 bits.
• Message blocks are encrypted and decrypted using a 192-bit key length by AES-192.
• Message blocks are encrypted and decrypted using a 256-bit key length using AES-256.

Each cipher uses cryptographic keys of 128, 192, and 256 bits, respectively, to encrypt and decrypt data in blocks of 128 bits. Ten, twelve, and fourteen encryption rounds are carried out to the 128-bit, 192-bit, and 256-bit keys, respectively.

A round of processing involves a number of processes, like mixing, transposition, and substitution of the plaintext input to create the final ciphertext output. The original data is secure and the encryption becomes more difficult to break the more rounds there are.

Many data transformations are carried out in AES. The data is first placed into an array, and then several encryption rounds are performed with the cipher transformations. Using a substitution table and an existing cipher, data substitution is the initial transformation.

With the exception of the first row, every data row is moved by one in the second transformation. The Hill cipher is used in the third transformation to combine columns. Each column, or data block, undergoes the final transformation using a distinct encryption key or a subset of it. Larger keys are needed for more rounds to complete.

The message recipient decrypts the message by using a copy of the cipher to remove the many encryption layers and return the ciphertext to plaintext. They can read the communication after conversion and be sure that no one else has intercepted or read it.

Applicability

AES development was initiated in 1997 by the National Institute of Standards and Technology, also known as NIST. AES was adopted as the standard method of encryption in June 2003 for securing classified information, including data from the government. In addition, it became the first open cipher that the National Security Agency has authorised for use in the public domain to protect national security systems and Top Secret data.

The ISO/IEC 18033-3 standard from the International Organisation for Standardisation also includes AES and describes block ciphers that improve data confidentiality.

One of the most widely used symmetric key cryptography algorithms nowadays for a variety of encryption uses in both commercial and government settings is AES. Here are a few examples −

• Information on storage devices, like USB drives and hard drives.
• Apps for electronic communication.
• Libraries for programming.
• Web Browsers.
• Compression of Files and Discs.
• Wireless Systems.
• Databases.
• Passwords and Login Credentials.
• VPNs.

Federal departments and agencies can use this standard if they decide that cryptographic protection is required for sensitive (unclassified) information, as that term is defined in P. L. 100-235.

This standard can be used in addition to, or instead of, other FIPS-approved cryptographic algorithms. Instead of using this standard, federal departments or agencies that use cryptographic devices to secure sensitive (unclassified) information can use the same devices to protect sensitive data.

Additionally, organisations outside of the federal government can adopt and apply this standard.

Features of AES

The main features of AES encryption is as follows −

• AES is a subset of Rijndael block cipher.
• It is a successor of Data Encryption Standard (DES) and is stronger and faster than DES.
• It is a symmetric key symmetric block cipher.
• It operates on 128-bit (16 bytes) data.
• The cipher key may be of 128, 192 or 256 bits.
• All computations are performed on bytes rather than bits.
• AES gives full specification and design details.
• It can be implemented using languages C and Java for software protection.

Analysis of AES

In present day cryptography, AES is widely adopted and supported in both hardware and software. Till date, no practical cryptanalytic attacks against AES has been discovered. Additionally, AES has built-in flexibility of key length, which allows a degree of ”future-proofing” against progress in the ability to perform exhaustive key searches.

However, just as for DES, the AES security is assured only if it is correctly implemented and good key management is employed.

Advantages

Comparing the AES algorithm to prior algorithms like the Data Encryption Standard (DES), there are a number of benefits −

• Since AES uses several encryption rounds, it is more difficult to break and more difficult for attackers to intercept or steal encrypted data using brute-force attacks. As a result, AES offers higher protection.
• AES is an open source solution that is easily accessible, which lowers the cost of adoption and implementation.
• Due to its simplicity and flexibility, AES can be implemented in both software and hardware.
• Since the 2000 standard”s finalisation, research on AES encryption attacks has continued. Numerous investigators have disseminated assaults against AES variants with decreased rounds.

AES Security

• In order to protect official government data, the National Security Agency (NSA) authorised the use of AES (Advanced Encryption Standard) in 2003.
• It can handle keys with lengths of 192, 256, or 128 bits; longer keys are recommended for material that is more highly classified.
• While there have been AES attacks, most of them are conditional or unknown.
• Implementation flaws are used by side-channel attacks that have been demonstrated.
• Quantum computers can be a threat to AES-192 and AES-128, but AES-256 is generally unaffected.
• Taking everything into account, AES is still widely used and safe when used correctly.

Prevent Attack on AES

It is important to take the following actions to protect against AES encryption attacks and ensure the security of AES keys −

• Using secure passwords.
• Using password managers.
• Implement multifactor authentication and make it compulsory.
• Install antivirus and firewall programs.
• Provide security awareness training to staff members to protect them against phishing and social engineering scams.