| 摘要 |
PURPOSE:To prevent the deciphering of the ciphered software by decoding the ciphered software stored into a memory medium based on the cryptographic key stored in the memory of an IC card. CONSTITUTION:A writing device 1 is composed of a random number preparing device 2 and a ciphering device 3, an original software SW is ciphered by the ciphering device 3 based on the random number cryptographic key generated by the random number preparing device 2, and the ciphered software is stored into a recording area 5 of a recording medium 4 and into a memory 7 of a cryptographic key IC card 6. An IC card 6 has a ciphering part 8 having the same algorithm as the ciphering device 3 besides the memory 7 and a deciphering part 9 corresponding to the ciphering part 8. Thus, by equipping with a memory to store the cryptographic key into the IC card, the deciphering of the ciphered software is prevented. |
