## 2 Literature Review and Related Work  
Overall, ATMs play a crucial role in providing convenient and secure access to banking services. As the use of ATMs continues to grow, ensuring robust authentication methods becomes paramount in preventing fraudulent activities and protecting user data [20; 21; 22; 23; 24]. According to the latest literature [1; 6; 7; 8; 9; 10], some common ways of compromising the security of these electronic transaction methods are described further in the following for better understanding. * Stealing from the database Many retailers prefer to keep debit/credit card numbers in online databases to facilitate customer purchases. According to recent reports, attackers have breached merchant websites and stolen databases containing millions of debit/credit card details [1; 5], e.g., the compromising of Capital One, a US credit card issuer, which led to the exposure of 106 million customers' credit card information in 2019 [6], and the compromising of the TJX company chain, which led to the exposure of 94 million customers' credit card information in 2006 [6]. * Sniffing/packet intercepting During online debit/credit card payments, an attacker sniffs data packets to infer confidential payment information. In most circumstances, the attacker does not need to decrypt the presumably encrypted online payment packets (e.g., through Secure Sockets Layer) [1; 3; 5], but instead deceives the consumer into believing they are visiting a legitimate site while in fact, they are viewing the attacker's spoofing site. * Shoulder surfing An attacker stands nearby and observes a customer type in their credit/debit card number and other credentials or listens to the discussion if the consumer gives their credit/debit card information to some other party [2; 6]. * Skimming Fraudsters utilize this approach to collect sensitive information from a credit or debit card's magnetic strip [3; 6]. * Keypad overlays This is a technique that is meant to fit in with the normal ATM keypad and this allows it to go unnoticed. The overlay allows the keypad beneath it to work properly, allowing the person to operate the ATM without any difficulty; when a person punches their PIN onto the fake keypad installed over the existing ATM keypad, an overlay records and captures keystrokes (e.g., customer PIN). Simultaneously, the ATM card slot overlays/records the secret data from the ATM card's magnetic strip. Using blank cards, the fraudster combines information in their computer to clone the ATM card, and nowadays, this is becoming a significant threat [3]. Having provided a brief background to how overall electronic payment transactions are compromised by cyber criminals, the latter part of this section provides a brief review of available authentication methods for securing payment transactions. In general, ATMs are fundamentally autonomous banking workstations that are designed to offer easy transaction services to the customers that use them [3; 4; 25]. The fact that the ATM can provide its users service around the clock, seven days a week, is the primary advantage it offers [26; 27; 28; 29; 30]. ATMs are used at practically every convenient location in today's society, including busy streets, public spaces, and other areas. Despite the fact that ATMs have been an important part of our lives since the 1960s [3; 4; 5; 6], the authentication mechanisms that are used for transactions at ATMs have changed very little over the years [31; 32; 33; 34]. The security flaws inherent to magnetic media are the primary cause of the constraints imposed on ATMs' ability to protect their customer transactions. Since it is neither difficult nor costly to acquire the necessary equipment to encode magnetic stripes, the data stored on them are often encoded using two or three tracks [11; 12; 13; 14]. Later on, this weakness of magnetic stripe cards was somewhat remedied by the advent of smartcards that were compatible with EMV [11; 12; 13; 14; 35; 36; 37; 38]. The PIN of the cardholder is often the sole way to testify to the identity of the user.