The invention concerns a method for processing data in a blockchain. It aims at securely storing data issued from devices and going through a service platform by ensuring integrity and authenticity of the data. To this end, a list of device identifiers may by associated with respective decryption means in a blockchain platform. Upon reception (406) of a message comprising encrypted data and comprising a device identifier, the blockchain platform decrypts (407-409) the first encrypted data using the decryption means that are associated with the device identifier. The decrypted data is then hashed (409) and stored in the blockchain.