2DES is one of the implementation of #Data Encryption Standard (DES). It does two times DES algorithm on each block to encrypt# the message. Although it is an improvement to DES, it is still vulnerable to meet-in-the-middle (MITM) attack#.
The following uses mathematical notation to show the cryptographic scheme:
$$ \begin{aligned} C &= E_{K2}[E_{K1}[P]]\\ P &= D_{K1}[D_{K2}[C]] \end{aligned} $$