DES Full Form
What is the full form of DES?
The full form of DES is “Data Encryption Standard”. DES is also called a symmetric key algorithm in which encryption and decryption is done using only a single key. It was created in the 1970s by the IBM team and was adopted in 1977 to secure confidential data. This encrypts the data by dividing 64-bit data into smaller bits and encryption is done to get the 64-bit cipher text. It uses the 56-bit key for encryption and decryption purposes.
DES is an early encryption algorithm but at the start of the 21st century it was replaced by the Advanced Encryption Algorithm (AES) to get rid of brute force attacks and other cyber crimes. DES algorithms use several steps where each step is called round. Based on the size of data the number of rounds varies. In older days, it was used in storing personal information, financial transactions, entertainments, banking, online purchases and many others.
History of DES
DES was the result of significant changes that were made to the Cipher which is also known as LUCIFER in the year 1971. It was developed by Horst Fiestel, he was the cryptographer researcher of IBM. After the changes made to the LUCIFER, a proposal was made by the National Bureau of Standards (NBS) for the new national encryption standard which is known as DES. It became the approved encryption standard in November 1976 and reaffirmed as the standard in 1983. DES uses 16 rounds of Feistel structure in which different keys are used for different rounds. In 2002, DES was dominated by (Advanced Encryption Standard) AES. In the year 2005, AES was also replaced by another standard algorithm known as triple DES.
Characteristics of DES
Symmetric key algorithm is used.
Transposition cipher and substitution cipher is used.
Efficient algorithm for hardware uses.
The 56-bit key,which was the same for both encryption and decryption, initially was challenging to establish and was based on permutations.
DES algorithm
This algorithm consists of following steps:
At first, the Initial permutation is performed on the 64-bit plain text.
This divides the 64-bit plain text into two equal halves one is left plain text and the other is right plain text.
Both left and right plain texts undergo 16 rounds of the encryption process.
Then the left plain text and right plain text are combined and final permutation is performed on it.
Finally the result produced was the 64-bit cipher text.
Advantages of DES algorithm
As it uses the same key for both encryption and decryption, complexity is reduced.
It was specially designed for hardware rather than software, hence it shows fast and efficient implementation in hardware.
It was set as standard by the US government and other officials.
Disadvantages of DES algorithm
It is a weakly secured algorithm compared to AES and triple DES.
DES was less secured in case of brute force attack.
Deep crack machine is also available in the market which cracks the DES algorithm.
This algorithm is less efficient for software.
As it uses only a 56-bit key it is less secure than other algorithms.
Applications of DES
DES used in random number generation.
DES is used to develop a new form of algorithm known as triple DES.
Frequently Asked Questions (FAQs)
Data Encryption Standard is a common encryption algorithm which is mainly used to secure personal and confidential data. In this plain text is converted into cipher text which is not known by unauthorized users.
There are many changes made to the DES and advanced encryption standards are introduced like AES and triple DES. These are the advanced algorithms which are more secure than the DES and are good competitors of brute force attack. AES and triple DES use larger key sizes and are very efficient compared to DES.
DES consists of 16 stages which are also known as rounds. And also there is an initial and final permutation apart from this. Here the initial and final permutations are inverse to each other. In this cipher block is divided into two equal halves and permutation is done on this in a crisscross fashion.
At first, the 64-bit plain text is divided into two equal halves which are of 32 bit each. The feistel structure works on 32-bit data at one time. There are four stages of operations in the Feistel structure they are-expansion, key-mixing, substitution and permutation. Finally the result is the 64-bit cipher text after the completion of these four stages.
It is a most basic attack and it tries to attempt every possible key on the encoded text. Based on the key size it determines the total number of possible keys and tries all the possible keys against the encoded data.