Encryption and Decryption Algorithms in Symmetric Key Cryptography Using Graph Theory

The present-day society depends heavily on digital technology where it is used in many applications such as banking and e-commerce transactions, computer passwords, etc. Therefore, it is important to protect information when storing and sharing them. Cryptography is the study of secret writing which applies complex math rules to convert the original message into an incomprehensible form. Graph theory is applied in the field of cryptography as graphs can be simply converted into matrices There are two approaches of cryptography; symmetric cryptography and asymmetric cryptography. This paper proposes a new connection between graph theory and symmetric cryptography to protect the information from the unauthorized parties. This proposed methodology uses a matrix as the secret key which adds more security to the cryptosystem. It converts the plaintext into several graphs and represents these graphs in their matrix form. Also, this generates several ciphertexts. The size of the resulting ciphertexts are larger than the plaintext size.

Improving Semantic Parsing Using Statistical Word Sense Disambiguation (Student Abstract)

A Semantic Parser generates a logical form graph from an utterance where the edges are semantic roles and nodes are word senses in an ontology that supports reasoning. The generated representation attempts to capture the full meaning of the utterance. While the process of parsing works to resolve lexical ambiguity, a number of errors in the logical forms arise from incorrectly assigned word sense determinations. This is especially true in logical and rule-based semantic parsers. Although the performance of statistical word sense disambiguation methods is superior to the word sense output of semantic parser, these systems do not produce the rich role structure or a detailed semantic representation of the sentence content. In this work, we use decisions from a statistical WSD system to inform a logical semantic parser and greatly improve semantic type assignments in the resulting logical forms.

Complexity of propositional projection temporal logic with star

This paper investigates the complexity of Propositional Projection Temporal Logic with Star (PPTL*). To this end, Propositional Projection Temporal Logic (PPTL) is first extended to include projection star. Then, by reducing the emptiness problem of star-free expressions to the problem of the satisfiability of PPTL* formulas, the lower bound of the complexity for the satisfiability of PPTL* formulas is proved to be non-elementary. Then, to prove the decidability of PPTL*, the normal form, normal form graph (NFG) and labelled normal form graph (LNFG) for PPTL* are defined. Also, algorithms for transforming a formula to its normal form and LNFG are presented. Finally, a decision algorithm for checking the satisfiability of PPTL* formulas is formalised using LNFGs.