| 摘要 |
PROBLEM TO BE SOLVED: To provide a recording device capable of detecting deletion even when the whole of up-to-date records including a forgery detection cord are deleted. SOLUTION: A joint hash production part successively inputs data hashes and produces joint hashes T1, T2, etc. (described as T1, etc.) from the data hashes and successively outputs them. A hash management part successively stores T1, T2, etc. successively outputted from the joint hash production part. The joint hash control part monitors storage circumstances and storage order of T1, etc. successively outputs, when the subsequent T2 is stored after the initial T1 is stored, a pair of T1 and T2, when T3 is stored after T2, a pair of T3 and T2 are outputted and a pair of T1 and T3 are outputted, thereafter, when Tk (k is an integer of 4 or more) is successively stored, a pair of Tk and Tk-1 are outputted and a pair of Tk and T1 are outputted. An intermediate hash production part inputs each pair outputted from the joint hash control part and produces an intermediate hash from the pair every pair. COPYRIGHT: (C)2010,JPO&INPIT |
