I am working on an Project which collects sensordata and stores them on a sdcard. The user is later able to upload the data to a webpage for further processing.
I would like to ensure that the data is not tampered. The encryption itself is not necessary. Decryption is done offline so need for that on the Arduino. For a first approach time limitation is not an issue.
I am somewhat stuck, is generating a Hash for the data sufficient or do I need full asymetric encryption? Storing the encryption key on the device seems to be no option.