Method and apparatus for camouflaging of data, information and functional transformations

Restricted data, such as a secret key (140) used in a public key signature system, is made secure in a digital wallet (100) using "generation camouflage" technology. With this technology, even the form as which the secret key (140) was enciphered does not necessarily need to be memorized in a digital wallet (100). Instead, a wallet includes the secret key generation function (130) which carries out regeneration of the right secret key, when a user inputs PIN as which self was chosen beforehand. When PIN which the user mistook is inputted, the mistaken secret key (140) is outputted. Such a secret key (140) can be constituted so that it cannot distinguish from the right secret key (140) easily through use of the false public key corresponding to [use / a secret key format / and/or] a secret key (140). The technology explained in this specification is applicable also to the restricted data in which the regeneration of other forms other than a secret key is possible.