Method for executing falsification check of data transmitted from data recording device including processor and a/d converter, and data recording device for performing the method

A method for executing a falsification check of data transmitted from a data recording device, the data recording device comprising a processor and an A/D converter, the method comprising a first method performed by the data recording device and a second method performed by a user device:

• wherein the first method comprises:
• Step Sa 0 of preparing a public key;
• Step Sa1 of inputting an analog signal obtained by a sensor into the A/D converter, while the A/D converter generates whole digital data consisting of signal data and noise data that are determined according to S/N ratio of the data recording device,
• wherein the signal data consists of higher-order bits that are effectively used as significant data and the noise data consists of lower-order bits that are disregarded, and
• wherein the higher-order bits are stored in a signal area in the data recording device and the lower-order bits are stored in a noise area in the data recording device, the noise area being a data region regarded as noise and unused,
• Step Sa2 of computing a hash value using a hash function for only the signal data or for the whole digital data except the hash value;
• Step Sa3 of encrypting the hash value with the public key;
• and
• Step Sa4 of writing the encrypted hash value into the noise area where the noise data is recorded, while the digital data including the encrypted hash value generated by performing the first method is transmitted to the user device, and
• wherein the second method comprises:
• Step Sb1 of computing a hash value using the hash function for only the signal area of the whole digital data received by the user device or for the whole digital data received by the user device except the hash value;
• Step Sb2 of encrypting the hash value computed in Step Sb1 with the public key;
• Step Sb3 of comparing the encrypted hash value in the received data with the hash value decrypted in Step Sb2;
• and
• Step Sb4 of determining whether the data transmitted from the data recording device has been falsified on a basis of a result in Step Sb3.