A method for ensuring the integrity of data using a keyless secrecy coding protocol ensuring unconditional confidentiality of the data to be transmitted between at least one sender A and one recipient B, the method containing at least the following steps: a first initialisation step, in which sender A confidentially transmits a secret key k 0 to receiver B by using secrecy coding, a step of transmitting several messages x i containing the data to be transmitted, in which method: to transmit each message x i, sender A adds, to the message x i, a tag tag i, defined by tag i = h k 0 ( x i), by using a hash function h k 0 ( x i) known only to sender A and to recipient B, which is intended to guarantee the authentication and the integrity control of the transmitted data, the hash function h k 0 being dependent on the initial key k 0 transmitted confidentially by sender A to recipient B, by using the secrecy coding, the message x i ∗, composed of the message of the useful data x i and of the tag tag i is encrypted so as to produce a message C x i ∗, which is transmitted to recipient B, the encryption being carried out so as to guarantee confidentiality using secrecy coding, after transmission,, recipient B receives the message X i ∗ to which it applies secrecy decoding to retrieve a data message X i and the tag Tag i, then it checks the authentication and the integrity of the received useful message X i by verifying that the relation Tag i = h(X i) is indeed satisfied, guaranteeing X i = x i. a first initialisation step, in which sender A confidentially transmits a secret key k 0 to receiver B by using secrecy coding, a step of transmitting several messages x i containing the data to be transmitted, in which method: to transmit each message x i, sender A adds, to the message x i, a tag tag i, defined by tag i = h k 0 ( x i), by using a hash function h k 0 ( x i) known only to sender A and to recipient B, which is intended to guarantee the authentication and the integrity control of the transmitted data, the hash function h k 0 being dependent on the initial key k 0 transmitted confidentially by sender A to recipient B, by using the secrecy coding, the message x i ∗, composed of the message of the useful data x i and of the tag tag i is encrypted so as to produce a message C x i ∗, which is transmitted to recipient B, the encryption being carried out so as to guarantee confidentiality using secrecy coding, after transmission,, recipient B receives the message X i ∗ to which it applies secrecy decoding to retrieve a data message X i and the tag Tag i, then it checks the authentication and the integrity of the received useful message X i by verifying that the relation Tag i = h(X i) is indeed satisfied, guaranteeing X i = x i. to transmit each message x i, sender A adds, to the message x i, a tag tag i, defined by tag i = h k 0 ( x i), by using a hash function h k 0 ( x i) known only to sender A and to recipient B, which is intended to guarantee the authentication and the integrity control of the transmitted data, the hash function h k 0 being dependent on the initial key k 0 transmitted confidentially by sender A to recipient B, by using the secrecy coding, the message x i ∗, composed of the message of the useful data x i and of the tag tag i is encrypted so as to produce a message C x i ∗, which is transmitted to recipient B, the encryption being carried out so as to guarantee confidentiality using secrecy coding, after transmission,, recipient B receives the message X i ∗ to which it applies secrecy decoding to retrieve a data message X i and the tag Tag i, then it checks the authentication and the integrity of the received useful message X i by verifying that the relation Tag i = h(X i) is indeed satisfied, guaranteeing X i = x i.