Data security services with an algorithm-independant architecture

A different security level is offered and a user enables it to determine the security level of his own communication. The user can choose a low security level and can make a security-related overhead as small as possible. Otherwise, although accompanied by the increase in a security-related overhead, it is possible to choose a higher security level. : enciphering key with which a different security level is created by one or the use beyond it of two kinds of keys is used in order to encipher plaintext text data to a delta, it attests data using a message authentication key, and guarantees data integrity. It is made not to re-encipher data with each member of a tele space using two kinds of keys. The subgroup called "Tribe (tribe) " is formed in a tele space, and each Tribe enables it to adopt the security level of the tele space in which he is in another embodiment.