A television event may be consumed after been stored in a mass memory of a multimedia unit, but still fully relies on the security of a secure device. A conversion of a received content aims at firstly descrambling the content using control words included in entitlement control messages and immediately re-encrypting the descrambled content by a unique key generated specifically for this content. Access conditions attached to the entitlement control message containing the control word are temporarily stored and once the decryption is terminated, the secure device produces an information block. This information block containing for example access conditions and an identifier of the content is either stored into a secure memory of the secure device or stored in the mass memory with the encrypted content. The unique key is made up of a combination of a root key specific to the secure device and the information block.