| 摘要 |
A data encryption device for use in transferring data from one computer terminal to another comprises a first encryption unit to which input data for transmission is presented from the computer terminal and in which the input data is applied to the address lines (18) of a read-only memory (19) whereby to generate from the output of the read-only memory (19) data previously stored at the address location determined by the data, for transmission to the other computer terminal via a second encryption unit having a complementary read-only memory at the output of which the input data appears when the encrypted data is presented on its address lines. Each encryption unit has a second ROM, (26), with a memory map different to that of the first, so that encryption is different for each different direction of transmission. <IMAGE> |
