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THE MODIFIED SECURITY SCHEME FOR DATA INTEGRITY IN MANET

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A. Rajaram et. al. / International Journal of Engineering Science and Technology Vol. 2(7), 2010, 3111-3119 THE MODIFIED SECURITY SCHEME FOR DATA INTEGRITY IN MANET 1 A.Rajaram and 2Dr.S.Palaniswami 1 Anna University Coimbatore Coimbatore, India gct143@gmail.com 2 Registrar, Anna University Coimbatore Coimbatore, India joegct81@yahoo.com Abstract: In mobile ad hoc networks (MANETs), it is easy to launch wormhole, man-in-the-middle and denial of service (DoS) attacks, or to impersonate another node. Our previous work established a network consisting confidentiality and authentication of packets in both routing and link layers. As an extension to our previous work, in this paper, we propose to develop an enhanced distributed certificate authority scheme to provide data integrity, thus making the network more secure from both inside and outside attacks. The proposed scheme makes use of Shamir’s secret sharing scheme along with a redundancy technique to support certificate renewal and revocation. The malicious nodes are detected by the trusting mechanism by monitoring the behavior hop by hop. By simulation results, we show that the proposed scheme achieves more packet delivery ratio while attaining less delay and overhead, compared with the previous existing scheme. Keywords: Shamir’s Secret Sharing, denial of service (DoS), Routing cum forwarding (RCF), Certificate revocation, Certification revival. 1. Introduction 1.1. Mobile Ad-Hoc Network (MANET) A mobile ad-hoc network (MANET) is a temporary infrastructure less multi-hop wireless network in which the nodes can move arbitrarily. Such networks extend the limited wireless transmission range of each node by multi-hop packet forwarding, thus, well suited for the scenarios in which pre deployed infrastructure support is not available. In an ad hoc network, there is no fixed infrastructure such as base stations or mobile switching centers.The mobility of the routers are provided randomly and organized themselves arbitrarily; thus, the network's wireless topology may alter rapidly and unpredictably. [8] These types of networks function in the absence of any fixed infrastructure, which provides easy deployment. [7] However, due to the lack of any fixed infrastructure, it becomes complicated to exploit the present routing techniques for network services, and this provides some huge challenges in providing the security of the communication, which is not done effortlessly as the number of demands of network security conflict with the demands of mobile networks, largely due to the nature of the mobile devices (e.g. low power consumption, low processing load). [12] MANET has various potential applications, which are usually set up in situations of emergency for temporary operations or simply if there are no resources to set up elaborate networks. Some typical examples include emergency search-rescue operations, meeting events, conferences, and battlefield communication between moving vehicles and/or soldiers. [3] With the abilities to meet the new demand of mobile computation, the MANET has a very bright future. 1.2. Threats in MANET The broadcasting nature of transmission and the nodes self routing environment opens up the perception of security in MANET. The security issue of MANET is of large concern taking into account its various factors like its open network, mobility factor and other factors. When taking into security aspects, the attacks on MANET can be classified into two; internal attacks and external attacks [2, 5, 10, 17]. Internal attacks are those attacks which are caused by inside node of a network. These attacks are produced by either malicious nodes or by selfish nodes inside ISSN: 0975-5462 3111 A. Rajaram et. al. / International Journal of Engineering Science and Technology Vol. 2(7), 2010, 3111-3119 a network. These internal attacks are tough to detect as nodes affected by such an attack generate themselves the valid signatures using their private keys. Examples of internal attack are internal eavesdropping, where the nodes extracts copy of all information and exploited it without the knowledge of other nodes and packet dropping. In external attacks, the attackers are from outside the network but cause damage or compromises network within the network. Attacks from external nodes can be prevented from cryptographic techniques such as encryption and authentication. As per routing, external attacks can be divided into active and passive attacks. Active external attacks use to degrade or stops message flow between the nodes. DoS attacks, packet dropping or flooding of packets are some examples of active external attacks. Passive external attacks are formally done by compromising the nodes and extracting vital information of the network. In passive attack, the attacker does not disrupt the network operation but only extracts information to damage further network operation. These type of attacks are basically impossible to detect, thus making it hard to produce security for such attacks. 1.3. Security Challenges in MANET The nature of MANET makes it vulnerable to attacks. Challenges in MANET securities are discussed briefly [3]; Availability: should withstand survivability regardless of Denial-of-Service (DOS) attacks like in physical and media access control layer attacker uses jamming techniques for hinder with communication on physical channel. On network layer the attacker can interrupt the routing protocol. On higher layers, the attacker could bring down high level services e.g.: key management service. Confidentiality: should safeguard certain information which is not to be disclosed to unauthorized entities. Integrity: Transmitted Message should be genuine and should never be corrupted. Authentication: Enables a node to safeguard the characteristics of the peer node it is communicating, without which an attacker would duplicate a node, thus attaining unauthorized admission to resource and sensitive information and snooping with operation of other nodes. Non-repudiation safeguards that the source of a data should not reject having sent the data. 1.4.Problem Identification & Proposed Solution In mobile ad hoc networks (MANETs), it is simple to launch wormhole, man-in-the-middle and denial of service (DoS) attacks, or to impersonate another node. To resist against such attacks from outsider nodes, we propose a hopby-hop authentication protocol. It authenticates packets at every hop by using a certificate authority (CA) based approach and drops any packets that originate from outsiders. Each node monitors and evaluates the behavior of its successors by itself, and as soon as it accuses a node it launches a procedure to approve this accusation. In our previous work [11], we have analyzed about the confidentiality and authentication of data in MANET environment. In this paper, we analyze the integrity of data along with the external attack. 2. Related Work Rehan Akbani et.al. [1] have proposed a hop-by-hop, proficient authentication protocol, called HEAP. It authenticates packets at each hop using a modified HMAC-based algorithm including two keys and drops any packets that are initialized from outsiders. The method used here can be appropriate for all application like multicast, unicast or broadcast applications. Discovering an insider attack using this protocol is highly improbable. But if a third party intrusion detection system (IDS) happens to detect a compromised insider node and raise an alarm to other nodes, HEAP will offer a framework for an effective response system. Wenbo He et.al. [15] have proposed a self-contained public key-management scheme, a scalable means of cryptographic key management (SMOCK), which acquires negligible communication overhead for authentication, and offers maximum service availability. Here a combinatorial design of public-private key pairs is created which provides each node with extra protection of more than one key pair to encrypt and decrypt messages. This format helps in earning higher stability in terms of nodes and storage space. The scheme also achieves controllable resilience against node compromise by defining required benchmark resilience. Nitesh Saxena et.al [9] have discussed about various signature scheme and have studied about the various techniques used. Here they tried the threshold in constructing decentralized access control mechanisms for ad hoc groups. They tried to first, point out the drawbacks of known threshold RSA signatures and tried to build access control mechanisms based on a variety of flavors of distinct logarithm based threshold signatures in this paper they tried to implement three access control mechanisms based on discrete-logarithm based threshold signatures, threshold DSA (TS-DSA), threshold Schnorr (TS-Sch) and threshold BLS (TS-BLS). ISSN: 0975-5462 3112 A. Rajaram et. al. / International Journal of Engineering Science and Technology Vol. 2(7), 2010, 3111-3119 Nikos Komninos et.al [6] have proposed a two-phase detection procedure of nodes that are not authorized for specific services and nodes that have been compromised during their operation in MANET. The detection framework' is enabled with the major operations of ad hoc networking, which are found at the link and network layers. The proposed framework is based on zero knowledge techniques, which are particularly designed to achieve node identification but do not rely on symmetric or asymmetric encryption algorithms, digital signatures, sequence numbers and timestamps. The zero knowledge techniques are presented through proofs. Binod Vaidya et.al [14] have put forward AODV with Multiple Alternative Paths (AODV-MAP) scheme and its security extension SAODV-MAP scheme. AODV-MAP scheme is robust and efficient multipath ad hoc routing protocol. It was intended to have secured AODV-MAP in order to provide security against various attacks. Security analysis shows that SAODV-MAP is much more robust against various known adversaries than SRP. The simulation results show that SAODV-MAP is better than AODV and as efficient as AODV-MAP in discovering and maintaining routes. Overall, in presence of various malicious nodes, SAODV-MAP scheme outperforms SRP scheme in all of the performance metrics that we examined. In our previous work [11] we present a solution for node selfishness to attain confidentiality and authentication of packets in both routing and link layers of MANETs. The technique is a double phase; one for detecting and isolating the malicious nodes using the routing layer information and second phase is for link-layer security. For detecting and isolating the malicious nodes we use the packet forwarding by maintaining a trust counter for each node. A node is punished or rewarded by decreasing or increasing the trust counter. If the trust counter value falls below a trust threshold, the corresponding intermediate node is marked as malicious. this provides an efficient and more secure protocol, as we use only nodes which are stored in the current route need to perform this cryptographic computation as well as authentication is performed for route reply operation. For link-layer security, in the next phase, we use CBC-X mode of authentication and encryption. 3. Proposed Scheme In the paper, we add integrity factor into our work to secure the network. We provide a certificate authority scheme and increase the security to tackle both internal and external attacks. Our scheme is contributed with three components; Monitoring Routing cum forwarding (RCF) behavior Certificate revival. Certificate revocation. Monitoring Routing cum forwarding (RCF) behavior which is based on our previous work, involves detecting misbehaviors in both the routing as well as the packet forwarding in the network. Certificate revival uses a redundancy scheme [4] in which a node is allocated more than one key share by incorporating redundancy into the network. This mechanism guarantees that genuine nodes can continue to stay in the network by revival of their certificates along a periodical time period. Certificate revocation provides the authority to isolate any malicious nodes or regain the nodes which turn up to its best state after any attack or failure. Thus, Certificate revival and Certificate revocation added to our previous work brings forth the integrity factor along with confidentiality and authentication. 3.1. Monitoring: Routing Cum Packet Forwarding (RCF) Behavior Monitoring of routing packets and forwarding packets are done using our previous work of Trust based packet forwarding scheme by punishing or rewarding the nodes with decreasing or increasing a trust counter. Each intermediate node marks the packets by adding its hash value and forwards the packet towards the destination node. The destination node verifies the hash value and check the trust counter value. If the hash value is verified, the trust counter is incremented, other wise it is decremented. If the trust counter value falls below a trust threshold, the corresponding the intermediate node is marked as malicious. Before proposing the modification, we can analyze how the trust based packet forwarding scheme works from our previous work. Each node keeps track of the number of packets it has forwarded through a route using a forward counter (FC). Each time, when node n k receives a packet from a node ni , then n k increases the forward counter of node ni . FCni  FCni  1, i  1,2,  (1) The incremental value, saved in a data structure called Neighbor’s Trust Counter Table (NTT), of node n k is modified with the values of FCni . ISSN: 0975-5462 3113 A. Rajaram et. al. / International Journal of Engineering Science and Technology Vol. 2(7), 2010, 3111-3119 Similarly each node determines its NTT and finally the packets reach the destination D. When the destination D receives the accumulated RREQ message, it measures the number of packets received Prec . Then it constructs a MAC on Prec with the key shared by the sender and the destination. The RREP contains the source and destination ids, The MAC of Prec , the accumulated route from the RREQ, which are digitally signed by the destination. The RREP is sent towards the source on the reverse route R1. Each intermediate node along the reverse route from D to S checks the RREP packet to compute success ratio as, FCni SRi  (2) Prec Where Prec is the number of packets received at D in time interval t1 . The FCni values of ni can be got from the corresponding NTT of the node. The success ratio value SRi is then added with the RREP packet. For any node n k , if SR k is either minimum or maximum than SR min (where SR min is the minimum threshold value) the trust counter value is further decreased or increased respectively. The incentive value provided to each successful node helps in determining the trustworthiness of the node and shows the misbehaving nodes apart from the network. To increase the integrity of these forward packets we introduce certification revival scheme using redundancy of [15] to guarantee that genuine nodes can continue to stay in the network by revival of their certificates along a periodical time period. 3.2. Certification Revival scheme To communicate between the nodes inside the network, every legitimate node carries a certificate, issued by an offline certificate authority (CA). The certificate comprises of 3 basic fields: Node id (NID), Initiation time (IT) and Expiry time (ET). For CA, we use the concept of secret sharing based upon Shamir’s “secret sharing model” [13, 16] with the use of redundancy. Shamir’s secret sharing scheme provides security as well as is extendable and flexible. Along with redundancy the mobility factors of adhoc network becomes less concerned. 3.2.1. Shamir’s Secret Sharing Model The CA key is shared to a set of nodes using the Shamir’s secret sharing model. Using the model we provide secrecy among a set of nodes from N nodes such that at least k nodes are needed to reconstruct the secrecy among the nodes. Consider the set of nodes be P1, P 2, P3,  , Pn . Under such condition we follow the following steps. Step 1: Dealer D constructs polynomial f ( x) of degree (k  1) , f ( x)  a 0  a1 x  a 2 x 2  a 3 x 3    a k 1 x k 1 (3) Polynomial f (x) is constructed over finite field, then a 0  sec ret ( s ) . All other coefficients are random elements in the field. Step 2: Dealer D chooses n random distinct evaluation points: X j  0, and secretly distributes to each participants P j the share sharej ( s )  ( X j , f ( X j )), j  1,2,  , n (4) The above two steps provides a sharing key among subset of k shares out of n shares. To reconstruct the sharing, the model uses Lagrange interpolation, Step 3: Using the Lagrange interpolation the unique polynomial f (x ) such that degree f ( x)  k and f ( j )  sharej ( s) for j  1,2,  , k f ( x)  i1 f (i)  Li( X ) k (5) Where Li ( X ) is the Lagrange polynomial. Li ( X )  ISSN: 0975-5462  j  i( x  xj ) .  j  i( xi  xj ) (6) 3114 A. Rajaram et. al. / International Journal of Engineering Science and Technology Vol. 2(7), 2010, 3111-3119 We evaluate the above steps using an example for sharing and reconstructing the CA among the sets of nodes. Consider an example where n  6 , are the participant nodes, secret s  1234 , then as per the polynomial eq (2) we have, f ( x)  a 0  a1 x  a 2 x 2 (7) by taking a random value a1 and a 2 as 166 and 94, we get the equation as. f ( x)  1234  166 x  94 x 2 (8) Computing the above equation and distributing the above equation, we are provided with 6 points as (1, 1494); (2, 1942); (3, 2578); (4, 3402); (5, 4414); (6, 5614). This provides the sharing values for each node of the sets. We recreate the secret, if at least 3 nodes are present. Let us consider we have 3 random nodes, ( x 0 y 0 )  (2,1942) ; ( x1 y1 )  (4,3402) ; ( x 2 , y 2 )  (5,4414) . Using the above equations (5) and (6) equilibrium value of MeCpG steps (,+14 deg.) [31,44]. In comparison, methylation has a significantly lower stability cost when happening at major groove positions, such as 211 and 21 base pair from dyad (mutations 9 and 12), where the roll of the nucleosome bound conformation (+10 deg.) is more compatible with the equilibrium geometry of MeCpG steps. The nucleosome destabilizing effect of cytosine methylation increases with the number of methylated cytosines, following the same position dependence as the single methylations. The multiple-methylation case reveals that each major groove meth- PLOS Computational Biology | www.ploscompbiol.org 3 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning ylation destabilizes the nucleosome by around 1 kJ/mol (close to the average estimate of 2 kJ/mol obtained for from individual methylation studies), while each minor groove methylation destabilizes it by up to 5 kJ/mol (average free energy as single mutation is around 6 kJ/mol). This energetic position-dependence is the reverse of what was observed in a recent FRET/SAXS study [30]. The differences can be attributed to the use of different ionic conditions and different sequences: a modified Widom-601 sequence of 157 bp, which already contains multiple CpG steps in mixed orientations, and which could assume different positioning due to the introduction of new CpG steps and by effect of the methylation. The analysis of our trajectories reveals a larger root mean square deviation (RMSD) and fluctuation (RMSF; see Figures S2– S3 in Text S1) for the methylated nucleosomes, but failed to detect any systematic change in DNA geometry or in intermolecular DNA-histone energy related to methylation (Fig. S1B, S1C, S4–S6 in Text S1). The hydrophobic effect should favor orientation of the methyl group out from the solvent but this effect alone is not likely to justify the positional dependent stability changes in Figure 2, as the differential solvation of the methyl groups in the bound and unbound states is only in the order of a fraction of a water molecule (Figure S5 in Text S1). We find however, a reasonable correlation between methylation-induced changes in hydrogen bond and stacking interactions of the bases and the change in nucleosome stability (see Figure S6 in Text S1). This finding suggests that methylation-induced nucleosome destabilization is related to the poorer ability of methylated DNA to fit into the required conformation for DNA in a nucleosome. Changes in the elastic deformation energy between methylated and un-methylated DNA correlate with nucleosomal differential binding free energies To further analyze the idea that methylation-induced nucleosome destabilization is connected to a worse fit of methylated DNA into the required nucleosome-bound conformation, we computed the elastic energy of the nucleosomal DNA using a harmonic deformation method [36,37,44]. This method provides a rough estimate of the energy required to deform a DNA fiber to adopt the super helical conformation in the nucleosome (full details in Suppl. Information Text S1). As shown in Figure 2, there is an evident correlation between the increase that methylation produces in the elastic deformation energy (DDE def.) and the free energy variation (DDG bind.) computed from MD/TI calculations. Clearly, methylation increases the stiffness of the CpG step [31], raising the energy cost required to wrap DNA around the histone octamers. This extra energy cost will be smaller in regions of high positive roll (naked DNA MeCpG steps have a higher roll than CpG steps [31]) than in regions of high negative roll. Thus, simple elastic considerations explain why methylation is better tolerated when the DNA faces the histones through the major groove (where positive roll is required) that when it faces histones through the minor groove (where negative roll is required). Nucleosome methylation can give rise to nucleosome repositioning We have established that methylation affects the wrapping of DNA in nucleosomes, but how does this translate into chromatin structure? As noted above, accumulation of minor groove methylations strongly destabilizes the nucleosome, and could trigger nucleosome unfolding, or notable changes in positioning or phasing of DNA around the histone core. While accumulation of methylations might be well tolerated if placed in favorable positions, accumulation in unfavorable positions would destabilize the nucleosome, which might trigger changes in chromatin structure. Chromatin could in fact react in two different ways in response to significant levels of methylation in unfavorable positions: i) the DNA could either detach from the histone core, leading to nucleosome eviction or nucleosome repositioning, or ii) the DNA could rotate around the histone core, changing its phase to place MeCpG steps in favorable positions. Both effects are anticipated to alter DNA accessibility and impact gene expression regulation. The sub-microsecond time scale of our MD trajectories of methylated DNAs bound to nucleosomes is not large enough to capture these effects, but clear trends are visible in cases of multiple mutations occurring in unfavorable positions, where unmethylated and methylated DNA sequences are out of phase by around 28 degrees (Figure S7 in Text S1). Due to this repositioning, large or small, DNA could move and the nucleosome structure could assume a more compact and distorted conformation, as detected by Lee and Lee [29], or a slightly open conformation as found in Jimenez-Useche et al. [30]. Using the harmonic deformation method, we additionally predicted the change in stability induced by cytosine methylation for millions of different nucleosomal DNA sequences. Consistently with our calculations, we used two extreme scenarios to prepare our DNA sequences (see Fig. 3): i) all positions where the minor grooves contact the histone core are occupied by CpG steps, and ii) all positions where the major grooves contact the histone core are occupied by CpG steps. We then computed the elastic energy required to wrap the DNA around the histone proteins in unmethylated and methylated states, and, as expected, observed that methylation disfavors DNA wrapping (Figure 3A). We have rescaled the elastic energy differences with a factor of 0.23 to match the DDG prediction in figure 2B. In agreement with the rest of our results, our analysis confirms that the effect of methylation is position-dependent. In fact, the overall difference between the two extreme methylation scenarios (all-in-minor vs all-in-major) is larger than 60 kJ/mol, the average difference being around 15 kJ/ mol. We have also computed the elastic energy differences for a million sequences with CpG/MeCpG steps positioned at all possible intermediate locations with respect to the position (figure 3B). The large differences between the extreme cases can induce rotations of DNA around the histone core, shifting its phase to allow the placement of the methylated CpG steps facing the histones through the major groove. It is illustrative to compare the magnitude of CpG methylation penalty with sequence dependent differences. Since there are roughly 1.5e88 possible 147 base pairs long sequence combinations (i.e., (4n+4(n/2))/2, n = 147), it is unfeasible to calculate all the possible sequence effects. However, using our elastic model we can provide a range of values based on a reasonably large number of samples. If we consider all possible nucleosomal sequences in the yeast genome (around 12 Mbp), the energy difference between the best and the worst sequence that could form a nucleosome is 0.7 kj/mol per base (a minimum of 1 kJ/mol and maximum of around 1.7 kJ/mol per base, the first best and the last worst sequences are displayed in Table S3 in Text S1). We repeated the same calculation for one million random sequences and we obtained equivalent results. Placing one CpG step every helical turn gives an average energetic difference between minor groove and major groove methylation of 15 kJ/ mol, which translates into ,0.5 kJ/mol per methyl group, 2 kJ/ mol per base for the largest effects. Considering that not all nucleosome base pair steps are likely to be CpG steps, we can conclude that the balance between the destabilization due to CpG methylation and sequence repositioning will depend on the PLOS Computational Biology | www.ploscompbiol.org 4 November 2013 | Volume 9 | Issue 11 | e1003354 DNA Methylation and Nucleosome Positioning Figure 3. Methylated and non-methylated DNA elastic deformation energies. (A) Distribution of deformation energies for 147 bplong random DNA sequences with CpG steps positioned every 10 base steps (one helical turn) in minor (red and dark red) and major (light and dark blue) grooves respectively. The energy values were rescaled by the slope of a best-fit straight line of figure 2, which is 0.23, to por la lectura a través de la lectura de la prensa. La educación en los medios las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio adquiere pleno derecho y entidad en la sección sexta titulada «competencias sociales y cívi- técnico de los aparatos. cas» que indica que «los alum- nos deberán ser capaces de juz- gar y tendrán espíritu crítico, lo que supone ser educados en los las programaciones oficiales, ya que, a lo largo de un medios y tener conciencia de su lugar y de su influencia estudio de los textos, los documentalistas del CLEMI en la sociedad». han podido señalar más de una centena de referencias a la educación de los medios en el seno de disciplinas 4. Un entorno positivo como el francés, la historia, la geografía, las lenguas, Si nos atenemos a las cifras, el panorama de la las artes plásticas : trabajos sobre las portadas de educación en medios es muy positivo. Una gran ope- prensa, reflexiones sobre temas mediáticos, análisis de ración de visibilidad como la «Semana de la prensa y publicidad, análisis de imágenes desde todos los ángu- de los medios en la escuela», coordinada por el CLE- los, reflexión sobre las noticias en los países europeos, MI, confirma año tras año, después de 17 convocato- información y opinión rias, el atractivo que ejerce sobre los profesores y los Esta presencia se constata desde la escuela mater- alumnos. Concebida como una gran operación de nal (2 a 6 años) donde, por ejemplo, se le pregunta a complementariedad entre la escuela y los profesiona- los niños más pequeños si saben diferenciar entre un les de los medios, alrededor del aprendizaje ciudada- periódico, un libro, un catálogo, a través de activida- no de la comunicación mediática, este evento moviliza des sensoriales, si saben para qué sirve un cartel, un durante toda una semana un porcentaje elevado de periódico, un cuaderno, un ordenador si son capa- centros escolares que representan un potencial de 4,3 ces de reconocer y distinguir imágenes de origen y de millones de alumnos (cifras de 2006). Basada en el naturaleza distintas. Podríamos continuar con más voluntariado, la semana permite desarrollar activida- ejemplos en todos los niveles de enseñanza y práctica- des más o menos ambiciosas centradas en la introduc- Páginas 43-48 ción de los medios en la vida de la escuela a través de la instalación de kioscos, organización de debates con profesionales y la confección por parte de los alumnos de documentos difundidos en los medios profesionales. Es la ocasión de dar un empujón a la educación en medios y de disfrutarlos. Los medios –un millar en 2006– se asocian de maneras diversas ofreciendo ejemplares de periódicos, acceso a noticias o a imágenes, proponiendo encuentros, permitiendo intervenir a los jóvenes en sus ondas o en sus columnas Esta operación da luz al trabajo de la educación en medios y moviliza a los diferentes participantes en el proyecto. 5. La formación de los docentes La formación es uno de los pilares principales de la educación en los medios. Su función es indispensable ya que no se trata de una disciplina, sino de una enseñanza que se hace sobre la base del voluntariado y del compromiso personal. Se trata de convencer, de mostrar, de interactuar. En primer lugar es necesario incluirla en la formación continua de los docentes, cuyo volumen se ha incrementado desde 1981 con la aparición de una verdadera política de formación continua de personal. Es difícil dar una imagen completa del volumen y del público, pero si nos atenemos a las cifras del CLEMI, hay más de 24.000 profesores que han asistido y se han involucrado durante 2004-05. 5.1. La formación continua En la mayoría de los casos, los profesores reciben su formación en contextos cercanos a su centro de trabajo, o incluso en este mismo. Después de una política centrada en la oferta que hacían los formadores, se valora más positivamente la demanda por parte del profesorado, ya que sólo así será verdaderamente fructífera. Los cursos de formación se repartieron en varias categorías: desde los formatos más tradicionales (cursos, debates, animaciones), hasta actividades de asesoramiento y de acompañamiento, y por supuesto los coloquios que permiten un trabajo en profundidad ya que van acompañados de expertos investigadores y profesionales. Citemos, por ejemplo en 2005, los coloquios del CLEMI-Toulouse sobre el cine documental o el del CLEMI-Dijon sobre «Políticos y medios: ¿connivencia?». Estos coloquios, que forman parte de un trabajo pedagógico regular, reagrupan a los diferentes participantes regionales y nacionales alrededor de grandes temas de la educación en medios y permiten generar nuevos conocimientos de aproximación y una profundización. Páginas 43-48 Hay otro tipo de formación original que se viene desarrollando desde hace menos tiempo, a través de cursos profesionales, como por ejemplo, en el Festival Internacional de Foto-periodismo «Visa para la imagen», en Perpignan. La formación se consolida en el curso, da acceso a las exposiciones, a las conferencias de profesionales y a los grandes debates, pero añade además propuestas pedagógicas y reflexiones didácticas destinadas a los docentes. Estas nuevas modalidades de formación son también consecuencia del agotamiento de la formación tradicional en las regiones. Los contenidos más frecuentes en formación continua conciernen tanto a los temas más clásicos como a los cambios que se están llevando a cabo en las prácticas mediáticas. Así encontramos distintas tendencias para 2004-05: La imagen desde el ángulo de la producción de imágenes animadas, el análisis de la imagen de la información o las imágenes del J.T. La prensa escrita y el periódico escolar. Internet y la información en línea. Medios y educación de los medios. 5.2 La formación inicial La formación inicial está aun en un grado muy ini- cial. El hecho de que la educación en medios no sea una disciplina impide su presencia en los IUFM (Institutos Universitarios de Formación de Maestros) que dan una prioridad absoluta a la didáctica de las disciplinas. En 2003, alrededor de 1.400 cursillistas sobre un total de 30.000 participaron en un momento u otro de un módulo de educación en medios. Estos módulos se ofrecen en función del interés que ese formador encuentra puntualmente y forman parte a menudo de varias disciplinas: documentación, letras, historia-geografía Estamos aún lejos de una política concertada en este dominio. La optativa «Cine-audiovisual» ha entrado desde hace muy poco tiempo en algunos IUFM destinada a obtener un certificado de enseñanza de la opción audiovisual y cine. Internet tiene cabida también en los cursos de formación inicial, recientemente con la aparición de un certificado informático y de Internet para los docentes, dirigido más a constatar competencias personales que a valorar una aptitud para enseñarlos. 6. ¿Y el futuro? El problema del futuro se plantea una vez más por la irrupción de nuevas técnicas y nuevos soportes. La difusión acelerada de lo digital replantea hoy muchas cuestiones relativas a prácticas mediáticas. Muchos Comunicar, 28, 2007 47 Comunicar, 28, 2007 Enrique Martínez-Salanova '2007 para Comunicar 48 trabajos que llevan el rótulo de la educación en medios solicitan una revisión ya que los conceptos cambian. La metodología elaborada en el marco de la educación en medios parece incluso permitir la inclinación de la sociedad de la información hacia una sociedad del conocimiento, como defiende la UNESCO. En Francia, se necesitaría unir las fuerzas dispersas en función de los soportes mediáticos y orientarse más hacia la educación en medios que al dominio técnico de los aparatos. Los avances recientes en el reconocimiento de estos contenidos y las competencias que supondrían podrían permitirlo. Referencias CLEMI/ACADEMIE DE BORDEAUX (Ed.) (2003): Parcours médias au collège: approches disciplinaires et transdisciplinaires. Aquitaine, Sceren-CRDP. GONNET, J. (2001): Education aux médias. Les controverses fécondes. Paris, Hachette Education/CNDP. SAVINO, J.; MARMIESSE, C. et BENSA, F. (2005): L’éducation aux médias de la maternelle au lycée. Direction de l’Enseignement Scolaire. Paris, Ministère de l’Education Nationale, Sceren/CNDP, Témoigner. BEVORT, E. et FREMONT, P. (2001): Médias, violence et education. Paris, CNDP, Actes et rapports pour l’éducation. – www.clemi.org: fiches pédagogiques, rapports et liens avec les pages régionales/académiques. – www.ac-nancy-metz.fr/cinemav/quai.html: Le site «Quai des images» est dédié à l’enseignement du cinéma et de l’audiovisuel. – www.france5.fr/education: la rubrique «Côté profs» a une entrée «education aux médias». – www.educaunet.org: Programme européen d’éducation aux risques liés à Internet. dResedfeleexliobnuetsacón Páginas 43-48
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