KEY MANAGEMENT METHOD AND ITS SYSTEM

• Main Authors: KANDA MASASUKI, TANAKA KIYOTO, KURODA IKUKO
• Format: Patent
• Language: English
• Published: 30.07.1999
• Edition: 6
• Subjects: ADVERTISING; CODING OR CIPHERING APPARATUS FOR CRYPTOGRAPHIC OR OTHERPURPOSES INVOLVING THE NEED FOR SECRECY; CRYPTOGRAPHY; DISPLAY; EDUCATION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PHYSICS; SEALS; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

PROBLEM TO BE SOLVED: To provide a system such that each key storage agent keeps a correct partial key from the user and that parties other than the user cannot know the secret key. SOLUTION: A user 11i shares a partial key Sij with a plurality of key storage agent 12j(j=1, 2, 3). This sharing is conducted cooperatively by both parties according to a common key delivery method. The user 11I sums partial keys Sij to obtain a secret key Si, an agent 12j stores the partial key Sij for each user (i) and encrypts the key Sij with a system open information (g), and the result is sent to a key registration agent 13. The agent 13 multiplies the encrypted partial keys to obtain an open key Pi of the user (i) by encrypting the Si with the (g), and the open key Pi is registered for each user (i) and open to public.