ワンタイム is a free Android application developed by NTT DATA CORPORATION. It generates disposable passwords for authentication in online shopping. By using these one-time passwords, users can enjoy a more convenient and secure online shopping experience.

To use this app, certain conditions must be met. Users must have a card issued by a card issuer that has implemented the ワンタイム app service. They must also be registered for the card issuer's members-only online service and own a smartphone.

The usage process is simple. Users need to apply for the service through the card issuer's members-only online service, download and set up the app following the instructions provided in the email sent to their registered email address. When using the authentication service, users can launch the ワンタイム app and enter the generated one-time password in the designated field.

Please note that the download and initial setup of the app must be done following the instructions in the email. If users are already using the card issuer's authentication service with a fixed password, they will no longer be able to use the fixed password once they have completed the application for the one-time password through the card issuer's members-only online service. In such cases, users should promptly perform the initial setup of the ワンタイム app according to the provided instructions.

It is important to be aware that the settings and operations related to this app may not be completed successfully due to factors such as the communication status of the user's device. In such cases, users may need to reapply for the service.