Encryption system with time-dependent decryption

Abstract

An object of the invention is to provide an encryption system and method for inhibiting the decryption of encrypted data unless a decryption condition is satisfied. Thus, according to the present invention, in order to provide the encryption system for inhibiting the decryption of encrypted data unless a decryption condition is satisfied, decryption enabled time is designated as a decryption condition, and an encryption system incorporating time-dependent decryption is constituted by a time-key certificate and a time-key certificate manager. A time-key certificate is employed when a third party proves that a public encryption key added to the certificate satisfies the decryption condition. The time-key certificate manager issues a time-key certificate and then manages a decryption key.

Description

[0001] The present invention is directed to the field of encryption. It is more specifically directed to an encryption system.Background Art[0002] An explanation will be given for a difference between the use of a general certificate and the use of a time-key certificate.[0003] The use of a general certificate is shown in FIG. 1. When user B desires to encrypt data (M) and to transmit the encrypted data to user A, user B requests that a certification authority issue a certificate for user A. This certificate includes the name of user A and a public encryption key (KEa) for user A, and also the digital signature of the certification authority for all the contents. User B obtains the certificate for user A and confirms that the certification authority has provided the digital signature for the public encryption key for user A. If the digital signature is correct, user B encrypts the target message M by using the public encryption key (KEa) for user A, and transmits the encrypted messa...

AI Technical Summary

Benefits of technology

[0064] Since a user who performs encryption employs the time-key certificate of the present invention, he or she can encrypt data using his or her machine. And when the user acquires a time-key certificate, he or she can encrypt data in the same manner as for normal encryption by using a public encryption key included in the time-key certificate. As a result, the alteration of data or wiretapping during the communication process, which may occur when an external service is employed for encryption, can be prevented.[0065] Furthermore, when the correct signature of the time-key manager is included in the time-key certificate, the user performing the encryption can trust the decryption condition service provided by the time-key manager, which issued the time-key certificate, or by a person in charge of the server, so that an ID or a password used for an electronic safe system that satisfies a decryption condition need not be distributed to a person performing decryption.[0066] It is noted that this invention may be used for many applications. Although the description is made for particular arrangements and applications, the intent and concept of the invention is suitable and applicable to other arrangements and applications. It will be clear to those skilled in the art that other modifications to the disclosed embodiments can be effected without departing from the spirit and scope of the invention.

Problems solved by technology

However, a condition for limiting the time during which user A can decrypt data can not be added to the general certificate.

However, this technique does not teach a method for designating a time for enabling decryption of encrypted data.

Images