A Central-Entity centralizes users' personal and financial information in a secure environment in order to prevent the distribution of user's information in e-commerce. This information is then used to create digital identity for the users. The digital identity of each user is dynamic, non-predictable and time dependent, because it is a combination of a user name and a dynamic, non-predictable and time dependent secure code that will be provided to the user for his identification. The user provides his digital identity to an External-Entity such as merchant or service provider. The External-Entity is dependent on Central-Entity to identify the user based on the digital identity given by the user. The External-Entity forwards the user's digital identity to the Central-Entity for identification and authentication of the user and the transaction.