Security is a vital issue in the usage of Automated Teller Machine (ATM) for cash, cashless and many off the counter banking transactions. Weaknesses in the use of ATM machine could not only lead to loss of customer’ s data confidentiality and integrity but also breach in the verification of user’ s authentication. Several challenges are associated with the use of ATM smart card such as: card cloning, card skimming, cost of issuance and maintenance. In this paper, we present secure bio-cryptographic authentication system for Cardless ATM using enhanced fingerprint biometrics trait and encrypted Personal Identification Number (PIN). Fingerprint biometrics is used to provide automatic identification/verification of a legitimate customer based on unique feature possessed by the customer. Log-Gabor filtering algorithm was used for enhancing low image quality and effect of noise on feature extracted from customer’ s fingerprint minutiae. Truncated SHA 512/256 hash algorithm was used to secure the integrity and confidentiality of the PIN from sniffers and possible adversary within the channel of remote ATM banking transactions. Performance evaluation was carried out using False Acceptance Rate (FAR), False Rejection Rate (FRR) metrics and Collision Attack was performed on the Truncated SHA-512/256 hashed data (PIN). Results of the system performance shows Genuine Acceptance Rate (1-FRR) of 97. 5% to 100%, Equal Error Rate of 0. 0015% and Collision Attack carried out on the encrypted PIN message digest gave an unsuccessful attack. Therefore, the results of performance evaluation show the applicability of the developed system for secure Cardless ATM transaction.