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US 2004/0170277 A1Published application
Encryption/decryption method for data limited in value range, apparatus and program therefor
AssigneeCanon Kabushiki Kaisha
InventorsKeiichi Iwamura, Yuji Suga
Life of this patent
Estimating the term…
Abstract
On an encrypted object code obtained by encrypting an object code, there is discriminated whether an inhibited code defined in data format is present in a code concerning such encrypted object code, and, in case such inhibited code is judged absent, the encrypted object code is determined as an encryption result of the object code.
Claims30
An encryption method comprising:
- an encryption step of encrypting a code;
- an encryption result judgment step of judging whether a code, concerning an encrypted object code obtained by encrypting an object code by said encryption step, generates a code of a value within a predetermined range;
- and
- an encryption result determination step which, in case said encryption result judgment step identifies that a code of a value within the predetermined range is not generated, determines said encrypted object code as an encryption result of said object code.
1 more element
A decryption method comprising:
- a decryption step for decrypting an encrypted code;
- a decryption result judgment step of discriminating whether a code, concerning a decrypted object code obtained by decrypting an object code by said decryption step, generates a code of a value within a predetermined range;
- and
- a decryption result determination step which, in case said decryption result discriminating step identifies that a code of a value within the predetermined range is not generated, determines said decrypted object code as a decryption result of said object code.
1 more element
An encryption apparatus comprising:
- encryption means which encrypts a code;
- encryption result judgment means which judges whether a code, concerning an encrypted object code obtained by encrypting an object code by said encryption means, generates a code of a value within a predetermined range;
- and
- encryption result determination means which, in case said encryption result judgment means identifies that a code of a value within the predetermined range is not generated, determines said encrypted object code as an encryption result of said object code.
1 more element
A decryption apparatus comprising:
- decryption means which decrypts a code;
- decryption result judgment means which judges whether a code, concerning a decrypted object code obtained by decrypting an object code by said decryption means, generates a code of a value within a predetermined range;
- and
- decryption result determination means which, in case said decryption result judgment means identifies that a code of a value within the predetermined range is not generated, determines said decrypted object code as a decryption result of said object code.
1 more element
A computer readable program for encryption comprising:
- an encryption step for encrypting a code;
- an encryption result judgment step of judging whether a code, concerning an encrypted object code obtained by encrypting an object code by said encryption step, generates a code of a value within a predetermined range;
- and
- an encryption result determination step which, in case said encryption result judgment step identifies that a code of a value within the predetermined range is not generated, determines said encrypted object code as an encryption result of said object code.
1 more element
A computer readable program for decryption comprising:
- a decryption step of decrypting a code;
- a decryption result judgment step of judging whether a code, concerning a decrypted object code obtained by decrypting an object code by said decryption step, generates a code of a value within a predetermined range;
- and
- a decryption result determination step which, in case said decryption result judgment step identifies that a code of a value within the predetermined range is not generated, determines said decrypted object code as a decryption result of said object code.
1 more element
Dependencies are inferred from the claim text.