A device for managing multiple accesses to a secure module of a system on chip of an apparatus, and comprises a stream ciphering means arranged for computing on the fly and in a single pass an integrity check for data to be transferred between secure and non secure modules of the system on chip with a seed and an encryption key, and for encrypting/decrypting on the fly and in this single pass these data with the encryption key, and a control means for providing the encryption key and seed to the stream ciphering means and for requesting data transfer and retrieving status to the secure and non secure modules for allowing the transfer of encrypted/decrypted data between the secure and non secure modules.