TRANSMITTER FOR ENCODED DIGITAL INFORMATION AND CRYPTOGRAPHY KEY, DIGITAL MEDIA DEVICE, AND CRYPTOGRAPHY KEY MEDIUM DEVICE

PROBLEM TO BE SOLVED: To provide a new transmitter for encoded digital information and cryptography key, a digital media device, and a cryptography key medium device considering the usability of audiences while protecting copyright. SOLUTION: This transmitter for the encoded digital information and the cryptography key is provided with first digital media devices 101 and 103, the cryptography key medium device 106, and second digital media devices 105, 102, and 104. The first digital media devices encode the digital information by the cryptography key, output it to the second digital media devices as the encoded digital information, convert the cryptography key into a further encoded public key and output it to the cryptography key medium device. The second digital media devices decode the cryptography key from the public key inputted from the cryptography key medium device and decode the encoded digital information inputted from the first digital media devices by the cryptography key.