1. A method for preventing activation of hardware backdoors installed in a digital circuit, the digital circuit comprising at least one hardware unit to be protected, the method comprising: receiving by at least one obfuscation unit data intended to the at least one hardware unit, the data including an activation code to cause the activation of a hardware backdoor present in the at least one hardware unit; obfuscating the received data by the at least one obfuscation unit to generate obfuscated data, with the obfuscated data including an obfuscated activation code, and outputting the obfuscated data to the at least one hardware unit; processing the obfuscated data including the obfuscated activation code in the at least one hardware unit without the hardware backdoor being activated by the obfuscated activation code, and outputting the processed obfuscated data; and de-obfuscating the processed obfuscated data in at least one de-obfuscation unit after the processed obfuscated data is output by the at least one hardware unit.