Using the single crystal X-ray diffraction method, the title molecule ethyl-4-aminobenzoate oxalate monohydrate has been synthesized, crystallized and characterized. The Hirshfeld surfaces computational approach was used to analyze the intermolecular interactions in the crystal structure. The aforementioned compound crystallizes in a monoclinic crystal system of space group P21/c with the following cell parameters: a = 15.475(3), b = 5.7117(9), c = 14.029(3), = 101.764(6)º, V = 1214.0(4) 3 and Z = 4. The molecules in the crystal structure are connected by the N1-H1C···O7, O5-H2···O3, O7-H1···O4 and C8-H8A···Cg type intermolecular interaction, where Cg is the centroid of the ring. For the title molecule, the inter contact O···H (48.4%) contributes more to the Hirshfeld surfaces. The proton transfer from oxalic acid’s phenolic group to ethyl-4-aminobenzoate’s amine group, which results in the creation of salt, is revealed by the crystal structure. The ground state of ethyl-4-aminobenzoate oxalate monohydrate was also studied theoretically using the density functional method (DFT/B3LYP) with a basis set of 6–311++G(d,p). Charge transfer happens within the molecule, as shown by the computed HOMO and LUMO energies, DOS and MESP, as well as by the optimized molecular structure, electronic structural analysis and UV spectrum analysis.

Graph theory and cryptography maintain a profound theoretical relationship, especially concerning structural complexity and computational diculty. This paper investigates a new intersection by utilizing Rainbow Antimagic Edge Coloring on Flower Snark graphs, which are a type of non-Hamiltonian,non-3-edge-colorable cubic graphs for creating secure Cryptographic protocols. Rainbow Antimagic Coloring assigns distinct edge weights such that each vertex sums are unique, resulting in a one-way encoding system well-suited for encryption and hashing purposes. We illustrate how the challenge of computing valid Rainbow Antimagic Colorings for Flower Snark graphs can be leveraged to develop secure public key systems by encryption algorithm. The fundamental structural complexity of the Flower Snark graph allows for the establishment of Cryptographic primitives that are provably secure and resilient to both classical and quantum attacks.