Smart contracts are an important key component of blockchain technology. They allow the creation of unique digital assets (such as artwork, real estate, collectibles, etc.) by representing them as NFTs. These NFTs can then be sold and purchased transparently and securely on a decentralized NFT marketplace. In this paper, we develop a smart contracts application that allows the creation of an NFT, which represents an artwork, that can be sold on an NFT marketplace while transferring the ownership from the seller to the buyer.

In order to authenticate a user on an Automated Teller Machine (ATM) using Near Field Communication (NFC) technology embedded on smartphones, we recently proposed a new approach called Dynamic Array PIN Protocol (DAP) that allows a user to enter his PIN code in a secure manner. We proved that the DAP protocol is resistant to 13 different attacks. Furthermore, by comparing it to several existing solutions, we demonstrated that DAP is much better and more cost effective. However, after a thorough analysis, we discovered that the DAP protocol is vulnerable to multiple eavesdropping video or camera records attack. Consequently, in this paper, we aim to address this vulnerability by proposing a new security solution that improves the DAP protocol.