| 摘要 |
1. Apparatus for the coded transmission of information, comprising a coding section at the transmission end and a decoding section at the receiving end, the two sections each comprising a key store (110), a code generator (3), a mixer (4) and a synchronization stage (5), the code generators each generating a code sequence, the said sequences being identical at the transmission and receiving ends and being each dependent upon part of the key information stored the associated key stores (110), the mixer (4) at the transmission end mixing said code sequence with the clear information to form the coded message while the mixer (4) at the receiving end mixes said sequence with the coded message to form the original clear text, the synchronization stage (5) providing synchronism between the code generators (3) at the transmission and receiving ends and the stages co-operating therewith, synchronization being provided, for example, by controlled delay networks (6, 7), characterized - in that means (120, 130-134) are provided at the transmission and receiving ends, said means continually renewing the key information operative in the code generators (3) by block-wise or bit-wise read-out of new information from the key stores (110) at predetermined times and/or at predetermined intervals of time, the key stores (110) containing a key information supply adequate for a relatively long period, e.g. approximately one year, - in that the key stores (110) are disposed in separate, closed key containers (10) detachably connected to the coding and decoding sections, - and in that the key containers (10) are provided with a time window circuit (120, 130-134) which cannot be influenced from outside the containers (10) and which provents the read-out-of information from the key stores (110) outside the predetermined times or intervals of time. |
