Japan's Aeon Bank has enabled customer transactions that are authenticated using finger vein recognition technology.The lender, affiliated with retail giant Aeon Co., is the first bank in Japan that has offered a service requiring only biometric authentication.The bank carried out demonstration tests for transactions using fingerprint information last year. To improve safety, the bank decided to use information on customers' veins as well.The new service became available first at counters at five retail outlets, including in Tokyo and the central prefecture of Aichi, as well as at automated teller machines.It plans to expand the service to all its domestic outlets in the first half of fiscal 2018.In 2015, Aeon Bank revealed an ATM that lets customers authenticate transactions with just a fingerprint scan, saying it was the first Japanese bank to do so