A method is for protecting an encrypted content, by use of at least one
encryption key. The method includes generation of a temporary encryption
key, encryption by the temporary key of a value allowing the
determination of the encryption keys of the content, transmission of the
encrypted value to a multimedia unit, and encryption and transmission of
at least two cryptograms including the temporary key encrypted by an
authorization key. The first cryptogram is encrypted by a first
authorization key pertaining to a first security module and the second
cryptogram is encrypted by a second authorization key pertaining to a
group of security modules whose first security module is excluded.