Information transfer system, encryption device, and decryption device using elliptic curve cryptography

Abstract

To provide a content delivery system which enables a ciphertext to be reduced in size when using the ElGamal cipher. A content delivery device performs elliptic curve encryption on a content key, generates an encrypted content key that includes an x coordinate of an elliptic curve point obtained by the elliptic curve encryption, and outputs the encrypted content key. A content reception device receives the encrypted content key, and calculates a y coordinate of the elliptic curve point using the x coordinate included in the encrypted content key. The content reception device then performs elliptic curve decryption using the elliptic curve point and other information included in the encrypted content key, to generate a decrypted content key.

Description

Technical field [0001] The present invention relates to secret information transmission technology, which uses cryptography for information security. Background technique [0002] In recent years, cryptography has been used in various fields to communicate securely without exposing the content of the communication to third parties. [0003] For example, when a storage medium such as a DVD is transferred, in which content such as music or movies is recorded on the DVD, or when the content is transmitted to many users through a network, the content is encrypted to prevent unauthorized use. [0004] There are mainly two types of cryptography: secret key cryptography and public key cryptography. In secret key cryptography, the same key is used for encryption and decryption. Therefore, the sender (to perform encryption) and the receiver (to perform decryption) must share the key in advance. In public key cryptography, different keys are used for encryption and decryption, and the decr...

AI Technical Summary

Problems solved by technology

[0033] Thus, the elliptic curve ElGamal achieves a higher level of security when compared to other cryptogra...

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