  Using cryptography to protect information and communication has bacically two
major drawbacks. First, the specific entropy profile of encrypted data makes
their detection very easy. Second, the use of cryptography can be more or less
regulated, not to say forbidden, according to the countries. If the right to
freely protect our personal and private data is a fundamental right, it must
not hinder the action of Nation States with respect to National security.
Allowing encryption to citizens holds for bad guys as well.
  In this paper we propose a new approach in information and communication
security that may solve all these issues, thus representing a rather
interesting trade-off between apparently opposite security needs. We introduce
the concept of scalable security based on computationnally hard problem of
coding theory with the PERSEUS technology.
  The core idea is to encode date with variable punctured convolutional codes
in such a way that any cryptanalytic attempt will require a time-consuming
encoder reconstruction in order to decode. By adding noise in a suitable way,
that reconstruction becomes untractable in practice except for Intelligence
services that however must use supercomputers during a significant, scalable
amount of time. Hence it limits naturally any will to unduly performs such
attacks (eg. against citizens' privacy).
  On the users' side, encoder and noise parameters are first exchanged through
an initial, short HTTPS session. The principles behind that approach have been
mathematically validated in 1997 and 2007. We present the PERSEUS library we
have developed under the triple GPL/LGPL/MPL licences. This library can be used
to protect any kind of data.
