Patent ID: 7849319

Claim:
An electronic information processing device for encrypting main information, data of said main information including a group of data units, said main information comprising a plurality of MIDI events, said electronic information processing device comprising a hardware encoder comprising: a first section that incorporates data of encrypting information, representative of an encrypting procedure, dispersedly into particular ones of the data units belonging to a predetermined first data group of said main information, said encrypting information being scramble decoding data representative of one of a plurality of types of algorithms to be used for the encrypting procedure, the scramble decoding data comprising data of a plurality of bits, wherein said first section, generates, for each of the bits of the scramble decoding data, a first bit flag in accordance with a logical value of the bit, generates a second bit flag of a plurality of bits on the basis of logical values of the data units belonging to the predetermined first data group, and rewrites values of the MIDI events in the data units belonging to the predetermined first data group using the first and second bit flags; and a second section that executes the encrypting procedure on the data belonging to a predetermined second data group, different from the first group, of said main information using the algorithm of the type represented by the scramble decoding data.