Message authentication computationally constrained environments pdf

Data confidentiality is the most important issue in network security. Every network with any security focus will typically address this problem first. In sensor networks, the confidentiality relates to the following. A sensor network should not leak sensor readings to its neighbors. Especially in a military application, the data stored in the sensor node may be highly sensitive.

In many applications nodes communicate highly sensitive data, e. Public sensor information, such as sensor identities and public keys, should also be encrypted to some extent to protect against traffic analysis attacks. The standard approach for keeping sensitive data secret is to encrypt the data with a secret key that only intended receivers possess, thus achieving confidentiality.

While remarkable for its simplicity and speed in software,Description. RC4 generates a pseudorandom stream of bits a keystream which, for encryption, is combined with the plaintext using bit-wise exclusive-or; decryption is performed the same way since exclusive-or is a symmetric operation. To generate the keystream, the cipher makes use of a secret internal state which consists of two parts: A permutation of all possible bytes denoted "S" below. The permutation is initialized with a variable length key, typically between 40 and bits, using the key-scheduling algorithm KSA.

Once this has been completed, the stream of bits is generated using the pseudo-random generation algorithm. The key scheduling algorithm is used to initialize the permutation in the array "S". First, the array "S" is initialized to the identity commutation. S is then processed for iterations in a similar way to the main PRGA algorithm, but also mixes in bytes of the key at the same time.

The lookup stage of RC4. For as many iterations as are needed, the PRGA modifies the state and outputs a byte of the keystream. Each value of S is swapped at least once every iterations. Many stream ciphers are based on linear feedback registers LFSRs , which while efficient in hardware are less so in software. The design of RC4 avoids the use of LFSRs, and is ideal for software implementation, as it requires only byte manipulations. It uses bytes of memory for the state array, S[0] through S[], k bytes of memory for the key, key[0] through key[k-1], and integer variables, i, j, and k.

Performing a modulus can be done with a bitwise AND with or on most platforms, simple addition of bytes ignoring overflow. With the implementation of confidentiality, an adversary may be unable to steal information.

The adversary can change the data, so as to send the sensor network into disarray. For example, a malicious node may add some fragments or manipulate the data within a packet. This new packet can then be sent to the original receiver.

Data loss or damage can even occur without the presence of a malicious node due to the harsh communication environment. Thus, data integrity ensures that any received data has not been altered in transit. SHA hash functions. SHA-1 is the best established of the existing SHA hash functions, and is employed in several widely used security applications and protocols.

Simulators in simulate WSNs. This section describes the SHA1 algorithm - a 6-step process of padding of ' Task 1. Appending Padding Bits. The original message is "padded" extended so that its length in bits is congruent to , modulo The padding rules are:. Task 2. Appending Length. The rules of appending length are:. If overflow happens, only the low-order 64 bits are used. Task 5. A specific implementation, based on DECIM v2 , a highly scrutinized stream cipher, was presented and analyzed in detail.

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Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced. Explore Documents. Message Authentication in Computationally Constrained Environment. Uploaded by riskbaskar Document Information click to expand document information Description: PPT for message authentuication. Original Title Message Authentication in computationally constrained environment Ppt. Skip to Main Content. A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity.

Use of this web site signifies your agreement to the terms and conditions. Message Authentication in Computationally Constrained Environments Abstract: RFID and wireless sensor networks exemplify computationally constrained environments, where the compact nature of the components cannot support complex computations or high communication overhead.