DES-DES approach

In the Financial Transaction Service( FinTS), the former Home Banking Computer Interface( HBCI), various combined encryption methods are used to encrypt the message and ensure confidentiality between server and client; in addition to the RSA- DES hybrid, the DES-DES method(DDV) is also used.

In the DES-DES method, the message is encrypted using symmetric encryption, which means that the same key is used for encryption and decryption. The bank must also know this key. The message key, on the other hand, is encrypted using Triple DES( 3DES). Both are transmitted together.