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Rene Ndoundam

Publications and source records attributed to Rene Ndoundam.

5 recordsLinked to original sources

A Novel Approach of Pseudorandomly sorted list-based Steganography

We propose a new model of steganography based on a list of pseudo-randomly sorted sequences of characters. Given a list $L$ of $m$ columns containing $n$ distinct strings each, with low or no semantic relationship between columns taken two by two, and a secret message $s \in \{0,1\}^*$, our model embeds $s$ in $L$ block by block, by generating, for each column of $L$, a permutation number and by reordering strings contained in it according to that number. Where, letting $l$ be average bit length of a string, the embedding capacity is given by $[(m-1)*log_2(n!-1)/n*l]$. We've shown that optimal efficiency of the method can be obtained with the condition that $(n >> l)$. The results which has been obtained by experiments, show that our model performs a better hiding process than some of the important existing methods, in terms of hiding capacity.

cs.CR↗

Steganography and Broadcasting

Informally, steganography is the process of exchanging a secret message between two communicating entities so that an eavesdropper may not know that a message has been sent. After a review of some steganographic systems, we found that these systems have some defects. First, there are situations in which some concealment algorithms do not properly hide a secret message. Second, to conceal one bit of a secret message, some ask at least five documents and make at least two sampling operations, thus increasing their run-times. Considering the different ways to communicate with the receiver, we propose two steganographic systems adapted to the email communication whose algorithms are deterministic. To hide one bit of a secret message, our steganographic systems need only one document and performs one sampling operation and therefore significantly reduces the run-time.

cs.CR↗

PDF Steganography based on Chinese Remainder Theorem

We propose different approaches of PDF files based steganography, essentially based on the Chinese Remainder Theorem. Here, after a cover PDF document has been released from unnecessary A0, a secret message is hidden in it using one of the proposed approaches, making it invisible to common PDF readers, and the file is then transmitted through a non-secure communication channel. Where each of our methods, ensure the condition that the number of inserted A0 is less than the number of characters of the secret message s.

cs.CR↗

Hash function based on arithmetic coding and public-key cryptography

We propose a hash function based on arithmetic coding and public-key cryptography. The resistance of the hash function to second preimage attack, collision and differential cryptanalysis is based on the properties of arithmetic coding as a non-linear dynamical system. The resistance of the hash function to first preimage attack is based on the public-key cryptography. The new hash function uses the strength of HMAC with the difference that it didn't need a secret key for calculating the hash (in this step, it uses one, two or three public -keys) and in the classical attack, an adversary need to break the public key algorithm or to have all the secret keys to perform his attack.

cs.CR↗

Collision-resistant hash function based on composition of functions

cryptographic hash function is a deterministic procedure that compresses an arbitrary block of numerical data and returns a fixed-size bit string. There exist many hash functions: MD5, HAVAL, SHA, ... It was reported that these hash functions are not longer secure. Our work is focused in the construction of a new hash function based on composition of functions. The construction used the NP-completeness of Three-dimensional contingency tables and the relaxation of the constraint that a hash function should also be a compression function.

cs.CR↗