| 摘要 |
An arrangement for providing secure transmission of information. The bulk of the information is transmitted over non-secure channels such as broadcast media which terminate on a plurality of receiving stations. However, a residue of data is transmitted over a protected channel, such as a point-to-point channel, established for example, by a telephone connection. Interception of a complete message, when only the bulk of the message is available, becomes very difficult. It becomes even more difficult if scrambling arrangements are used to select the particular bits of the data message that are transmitted over the secure channel. It becomes still more difficult, if the data transmitted over the secure channel, itself, alters the scrambling algorithm. <IMAGE> |
