Rom protection device

摘要: A ROM module 14 is coupled to a processor 10, which uses program and/or data information stored in 14. To protect the from unauthorized copying, key memory 11 10 and memory 15 module are arranged store identical keys. Two encryption decryption units 12 16, and 16 as shown, encode decode passing between The encryption may be applied either the addresses sent 14, coming it, or preferably both. register repeatedly writeable, which case initial transference proces­ sor must transmission, without encryption. Alternatively, once writeable, so that useable only with processor preset key.