The invention relates to a method for secure data transmission in connections between two functional modules of an electronic unit. A first module of a message of k bits in a word code of n bits is injection coded with a constant Hamming weight of w. The word of code is transmitted to a second module. An error signal is generated when the Hamming weight of the word of code of n bits, received by the second module, is different from w. In the absence of error, the code word is decoded, where k, w and n are whole numbers. The invention further relates to a corresponding electronic circuit.