Method for receiving a multimedia content scrambled using control words, this method comprising: - reception (101 a), by a security processor, of ECM (Entitlement Control Message) messages containing at least one cryptogram CW* for a control word CW allowing a multimedia content to be descrambled, - deciphering, by the security processor, of this cryptogram CW*, and - descrambling of the scrambled multimedia content on the basis of the deciphered control word CW, characterized in that the method likewise has the following steps: - at least one implementation of a captcha (Completely Automated Public Turing test to tell Computers and Humans Apart) that is specific to the security processor, from a reception terminal, the correct response from which is contained in a memory of the security processor and varies from one implementation to the other, this implementation involving transmission of the captcha to this reception terminal so as to trigger display thereof on a screen, this specific captcha being associated, by means of a predefined relationship, with an identifier of this security processor containing the correct response to this captcha so as to allow identification of this security processor on the basis of this captcha among a set of security processors, - the security processor acquires at least one response to this captcha and compares this response with the correct response contained in its memory, and - the security processor limits the descrambling of the cryptograms CW* if no response to this captcha corresponds to the correct response contained in the memory, and - interception of the transmitted captcha and identification of the security processor on the basis of the intercepted captcha. - reception (101 a), by a security processor, of ECM (Entitlement Control Message) messages containing at least one cryptogram CW* for a control word CW allowing a multimedia content to be descrambled, - deciphering, by the security processor, of this cryptogram CW*, and - descrambling of the scrambled multimedia content on the basis of the deciphered control word CW, - at least one implementation of a captcha (Completely Automated Public Turing test to tell Computers and Humans Apart) that is specific to the security processor, from a reception terminal, the correct response from which is contained in a memory of the security processor and varies from one implementation to the other, this implementation involving transmission of the captcha to this reception terminal so as to trigger display thereof on a screen, this specific captcha being associated, by means of a predefined relationship, with an identifier of this security processor containing the correct response to this captcha so as to allow identification of this security processor on the basis of this captcha among a set of security processors, - the security processor acquires at least one response to this captcha and compares this response with the correct response contained in its memory, and - the security processor limits the descrambling of the cryptograms CW* if no response to this captcha corresponds to the correct response contained in the memory, and - interception of the transmitted captcha and identification of the security processor on the basis of the intercepted captcha.