ENCRYPTION DEVICE, PROGRAM, AND METHOD

摘要

Provided is an encryption device having a high safety for confidential da ta when performing data communication and accumulation.The encryption device generates a pseudo-random number according to a secret key and applies the pseudo-random number sequence to a plain text so as to generate an encrypted text. An internal state used for generating the pseudo-random number sequen ce is an internal state based on the state in accordance with rearrangement of a finite number of numeric values. At least one of the temporary variable used for generation of the pseudo-random number sequence is a temporary var iable using the result of execution of a predetermined leftward or rightward rotate shift and depending on a number smaller than the number of internal state in accordance with the result of the linear or non-linear, or a combin ation of linear and non-linear using one or more numeric values of the inter nal state. The pseudo-random number generated is generated by performing cal culation by using one or more numeric values among the internal states and t he temporary variable.