The present invention concerns a method of generation of a secret key, shared between a first terminal and a second terminal. The key is generated from the impulse response of the transmission channel separating the two terminals. A first message representative of the impulse response estimated by the first terminal is transmitted to the second terminal. This message is encoded using a channel encoding and punctured at a rate which prevents any decoding if additional information is missing. The second terminal combines this first message with at least a part of a second message representative of the impulse response estimated by the second terminal in order to attempt to decode the first message. If the decoding is successful the secret key is generated by the second terminal from the first message thus decoded.