Cryptography – Particular algorithmic function encoding – Nbs/des algorithm
Patent
1996-03-29
1999-02-09
Cangialosi, Salvatore
Cryptography
Particular algorithmic function encoding
Nbs/des algorithm
380 21, 380 30, H04L 900
Patent
active
058704779
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an enciphering/deciphering device for performing at least one of encryption processing of data and decryption processing of enciphered data. Further, the present invention relates to an encryption/decryption communication system in which enciphering/deciphering devices are connected to each other through communicating means. The enciphering/deciphering device is the concept including an enciphering device for enciphering (encrypting) plaintext data, a deciphering device for deciphering (decrypting) ciphertext data, and a device for performing both encryption processing and decryption processing. Similarly, an enciphering/deciphering method is the concept including a method of enciphering plaintext data, a method of deciphering ciphertext data, and a method of performing both encryption processing and decryption processing. The encryption/decryption communication system is the concept including a communication system comprising an enciphering device, a communication system comprising a deciphering device, and a communication system comprising both the enciphering device and the deciphering device.
BACKGROUND ART
In order to prevent leakage of the contents of document data generated by a word processor, code data of a computer program, statistical data, total data, and the like, the data are enciphered.
Encryption processing has been conventionally performed using as a key used for enciphering data (an encryption key) a key entered from an input device such as a keyboard or a key selected from a key table stored in a device for performing encryption processing (a computer system, etc.).
In such a conventional method, however, an encryption key (=a decryption key) may, in some cases, be seen by a third person or orally conveyed to a third person due to carelessness of a person who performs encryption processing (a creator of ciphertext), whereby it is highly possible that the encryption key is known by the third person. Consequently, the secrecy of the data cannot be sufficiently held. When a manager of ciphertext other than the creator of ciphertext sees the contents of the ciphertext, the creator must inform the manager of a decryption key for each production of ciphertext. When the creator informs the manager of the decryption key, the decryption key may be known by the third person due to carelessness or the like. In addition, the management of a correspondence between the ciphertext and the decryption key also becomes complicated for both the creator and the manager.
Furthermore, generally in a company or the like, a staff member generates ciphertext, and his or her superior manages the ciphertext. In such a case, the superior desires to prevent the ciphertext from being deciphered and known by a third person due to carelessness of the staff member by making it impossible for the staff member to decipher the ciphertext. That is, the superior has a strong request to intensively manage the secrecy of the ciphertext.
DISCLOSURE OF THE INVENTION
An object of the present invention is to prevent a key used at the time of encryption from being easily known by a third person. An object of the present invention is to make it easy to manage a correspondence between ciphertext and a key used for encryption. An object of the present invention is to make it possible for a manager to intensively manage ciphertext.
An enciphering/deciphering device according to the first invention comprises data encryption key forming means for forming a data encryption key used for enciphering plaintext data, secret key forming means for forming a secret key used for enciphering the data encryption key formed by the data encryption key forming means, management key forming means for forming a management key used for enciphering the data encryption key formed by the data encryption key forming means, data enciphering means for enciphering the plaintext data using the data encryption key to form ciphertext data, first key enciphering means for enciphering the data encryption key us
REFERENCES:
patent: 5200999 (1993-04-01), Matyas et al.
patent: 5201000 (1993-04-01), Matyas et al.
"Protecting Public Keys and Signature Keys", by Dorothy E. Denning, Computer, vol. 16, No. 2, Feb. 1983, pp. 27-35.
"System for Safe User Certification by Single Control Information", by Ryumei Okamoto, et al, IN83-85-92, vol. 83, No. 253, Jan. 25, 1984.
Sasaki Minoru
Yoshikawa Hiroharu
Cangialosi Salvatore
Pumpkin House Incorporated
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