La gestion des DRM en perspective

Preliminary chapter : Technology with the help of the right

The need inherent in the installation of a management of the numerical rights comes owing to the fact that, at least on Internet, there is an increasing number of processes making it possible to circumvent the technical measurements installation on the various types of supports. In this respect, one will refer in a very didactic article of Shantanu Rastogi^4(*) in which the author delivers the various means quite simply to us, to have access to any type of files and to exchange them. without too many efforts

The principal list including/understanding the following techniques : the networks Peer to Peer (P2P), the newsgroup, the cat (via the Internet Relay Chat), the sites of auction sales, the protocol File Transfer Protocol (ftp), the shops «will warez», the aces, the patches, the generators of job numbers, the distribution of the images discs (Iso).

Section 1- technical preconditions

Before immersing themselves in the management itself of the DRM, wondering about operation inherent in this management of the rights is a paramount stage. It makes it possible to apprehend in all its width the implications as well technological as legal which are in plays.

Thus, one will study successively technologies of applicable cryptography as much for the protection of physical supports that for the access control and the use of the digital components and technologies of watermarking, usable for the recognition of the rights, but also the traceability, the analysis of audience or the fight against the counterfeit, etc

§1- Cryptology

Cryptology is heard here like E so many the concept of coding the data at ends of nondisclosure and nonreproduction.

Also, one will endeavor to consider the major concepts of cryptology for then harnessing itself to practically identify what that implies on the level of the protection of the contents.

With- major Concepts

Before returning more in detail in the problems of cryptology, a short recall of the concepts of cryptology will make it possible to dissociate cryptography with secret key (or symmetrical key) of cryptography with private/public key (or asymmetrical key). Indeed, cryptography with secret key is used mainly for the protected transfer of the messages and the documents. Cryptography with key private/public, more personal and more expensive in data-processing computing time, is used to quantify the most significant parts of the messages: it is at the base of the concepts of fingerprint, signature, seal, electronic envelope.

1- cryptology with secret key

In a system of use of cryptography with secret key the various speakers divide the same key which will be used with the transmitter with crypter the message and the receiver to decipher it.

The algorithm with secret key most known is^5(*) and insofar as it can be « broken », it is preferable, at ends of safety, to frequently change the key : what brings us to a system known as of hierarchical keys.^6(*)

Figure 1: Diagram of a transmission made safe by secret key.

* ⁴ Shantanu Rastogi, DIGITAL Piracy  : Techniques, 2003, 14p. http://www.techlex.org/library.htm

* ⁵ The increase in the computing power of the computers makes it possible from now on «to break», by testing all the 256 possible keys. «Competitions» were organized to this end: a system made up of the supercomputer OF Cracker of the EFF (Electronic Frontier Foundation) and of 100.000 PC working in network with Distributed.net thus could «break» one OF the of 22 hours at the beginning of 1999  ». Henceforth, the NSA prohibited the use of for the American administration and recommends from now on the TDES (triple OF, three OF successive with two or three different keys) and can be soon the AES (Advanced Encryption Standard) resulting from the Belgian algorithm Rijndael. City in Philippe Chantepie, Technical Measurements of Protection of works & DRMS, 1ère Left: an Inventory of fixtures, January 8, 2003, p. 46.

* ⁶ Ibid, p. 18.