Encryption, having sufficient concealment, is carried out through chaotic computation using integer arithmetic. There is provided a cipher generating device, for carrying out computation, for plain text information, to apply chaotic noise obtained using a mapping function for generating chaotic noise based on encrypted key data, to generate a cipher. This cipher generation device comprises parameter generation means 102 for generating a parameter string for use in chaotic computation based on the key data, chaotic noise generating means 103 for carrying out chaotic computation using the parameter string generated by the parameter generating means 102 and obtaining the chaotic noise, and scheduling means 104 for carrying out scheduling of the parameter string so as to cause a change in the parameter string every fixed cycle the parameter string is used in the chaotic computation.