Newtec EL170 - Page 176

Features
User Manual for EL170/970/470 IP Satellite Modulator/
Demodulator/Modem
version 4.2
175
SHAPING THE FUTURE OF SATELLITE COMMUNICATIONS
9.13.4.2 64-bit Keys
A similar process is used for the computation of encrypted content keys in the 64-
bit mode. The computation of the encrypted content key from a given content key
is depicted in the following figure.
DES
Encryp
Encrypted
Content Key
Group Key
Content Key
64 bits
64 bits
64
bits
Key
Data in
Data out
Figure 121 - Process to Encrypt a Content Key with a Specific Group Key in 64-bit Mode
The DES algorithm used is the one described in the FIPS-46-3 standard from the
NIST.
The following lines provide a few examples of key computations for reference:
Example 1:
Content Key: 278da56a0f06aa1f
Group Key: fb5f9c585dd359aa
Encrypted Content Key: bf561dd5e15890b7
Example 2:
Content Key: 1234567890abcdef
Group Key: fb5f9c585dd359aa
Encrypted Content Key: d46f63e2cc998eec
Example 3:
Content Key: 1234567890abcdef
Group Key: 7fae81fad3154384
Encrypted Content Key: be407096c6104b1e