Triple DES Encryption and Decryption
Triple DES (3DES), also known as TDEA (Triple Data Encryption Algorithm), is a symmetric-key block cipher that applies the DES (Data Encryption Standard) cipher algorithm three times to each data block. It was developed to provide a higher level of security than the original DES, which became vulnerable to brute-force attacks due to advances in computational power.

Triple DES applies the DES algorithm three times with either two keys or three keys:

2-Key Triple DES: The first and third keys are the same (i.e., K1 = K3), and only two unique keys are used.
3-Key Triple DES: The first, second, and third keys are all different, providing a higher level of security.
The primary advantage of Triple DES is that it uses a stronger key length (168 bits for 3-key DES), which increases the security compared to regular DES (56 bits).

How Triple DES Works
Encryption: Triple DES applies the DES algorithm three times:
Encrypt with the first key (K1).
Decrypt with the second key (K2).
Encrypt again with the third key (K3).
Decryption: The decryption process reverses the encryption process:
Decrypt with the third key (K3).
Encrypt with the second key (K2).
Decrypt with the first key (K1).
Modes of Operation
Triple DES can be used with different modes of operation to enhance security:

ECB (Electronic Codebook): Each block is encrypted separately.
CBC (Cipher Block Chaining): Each block of plaintext is XORed with the previous ciphertext block before encryption, making it more secure than ECB.
CFB (Cipher Feedback) and OFB (Output Feedback): Provide feedback for encrypting data in smaller units than the block size.
Example: Triple DES Encryption and Decryption
Here is an example of how Triple DES (3DES) can be implemented in various programming languages. The example demonstrates how to encrypt and decrypt text using Triple DES with 3 keys.

Summary of Triple DES
Triple DES (3DES) applies the DES algorithm three times, providing a stronger encryption method than regular DES.
It supports both 2-key and 3-key versions, with 3-key being more secure.
It is a block cipher, meaning it encrypts data in fixed-size blocks (64 bits in the case of DES).
Triple DES is no longer considered secure for modern use due to its relatively small key size and vulnerabilities that make it susceptible to attacks like birthday attacks.
For modern applications, it is recommended to use more secure algorithms like AES (Advanced Encryption Standard). Triple DES remains in use in legacy systems, especially for backward compatibility or in scenarios where security is not a critical concern.