DES is an acronym for Data Encryption Standards. It is a technique to encrypt any plain text using a 56-bit key. Advancements in technology have led to the development of new methods that can easily crack a DES-encrypted text.
To prevent this, another encryption technique named Triple-DES was introduced. This method is much more secure than the original DES, and it uses a 168-bit key.
Triple-DES operates in three steps:
It uses three different independent keys. The keys are referred to as key1, key2, and key3.
First and foremost, the plain text is encrypted through the DES algorithm and key1. The output of the first step serves as the input of the next step.
In the second step, the ciphertext obtained from the previous step is decrypted using the REVERSE-DES algorithm and key2. Again, the output of the second step serves as the input of the next step.
In the third and final step, the text obtained from the previous step is again encrypted using the DES algorithm and key3.
The decryption of a ciphertext is a reverse process: Decrypt-Encrypt-Decrypt.
Note: Triple-DES has two-key and three-key versions. In the two-key version, the same algorithm is used, but key K1 is used for the first and last step, i.e., key1 = key3.
Triple-DES is a very strong encryption algorithm. However, it is still vulnerable to:
According to NIST’s guidance that was published on July 19, 2018, the Triple-DES is officially retired. The guidelines propose that Triple-DES is deprecated for all new applications, and its usage is disallowed after 2023.
According to NIST terminologies:
- Deprecated means “the use of the algorithm and key length is allowed, but the user must accept some risk.”
- Disallowed means an “algorithm or key length is no longer allowed for the indicated use.”