BISS mode 1• BISS mode 1 uses a 12 digit hexadecimal key as session word. The session word has to be announced to all parties that are allowed to descramble the received data.• Example : 123456ABCDEF• “BISS mode E• The session word can easily be compromised, there is no protection when communicating it to the receive site.
BISS mode E : scrambled with encrypted session word(ESW)• This mode uses the ID (identifier) of the receiver(s) and a session word to calculate an encrypted session word(16 digits hex)• There are two possible IDs - buried ID- injected ID• By encrypting the session word there is an additional protection on the session word. The ESW can be communicated using a non-secure channel since in order to descramble the received signal both the ID and the ESW need to be known.
Calculation of encrypted session word 1.Define a SW 2. Get the IDExchange ESWEnter ESW in IRD(s) 3.Calculate ESW To calculate the ESW 4. the DES algorithm is used