Secure data exchange

A method for secure data exchange is provided. The method comprises: concatenating, by a sender device, data to be exchanged with a random value; obtaining, by the sender device, a hash value of the data concatenated with the random value, using a hash function; digitally signing, by the sender device, the data concatenated with the random value using a private key of a user of the sender device, thereby generating a digital signature of the user of the sender device; storing, in a blockchain by the sender device, the hash value with the digital signature of the user of the sender device; receiving, by a receiver device, data to be verified and the random value; concatenating, by the receiver device, the received data with the random value; obtaining, by the receiver device, a hash value of the received data concatenated with the received random value, using the hash function; determining, by the receiver device, whether or not the hash value of the received data concatenated with the received random value is stored in the blockchain; determining, by the receiver device, that the received data is the data to be exchanged, in case: the hash value of the received data concatenated with the received random value is stored in the blockchain; and the digital signature stored in the blockchain in association with the hash value of the received data concatenated with the received random value is determined to be valid using a public key of the user of the sender device.