Files with the .DC4 extension contain encrypted data in a binary format, which can also be compressed. The file is unique to the (De)Coder software created by Daniel Marschall. The data can be coded using various methods of encryption, including the option to require a password to access the data.

The program that makes use of DC4 files guarantees a high degree of security. It allows the use of the line of command interface, as well as the “Drag and drop” functionality for coding and decoding the file.