Data processing system and data processing method for authenticating user by utilizing user list obtained from service providing apparatus

1. A data processing system comprising:

a service using apparatus; and

a data processing apparatus that provides a service to the service using apparatus,

wherein the service using apparatus includes

a processor; and

a memory storing instructions that, when executed, cause the processor to function as;

an authentication requesting unit that requests, based on a request to authenticate from a user accepted via an input screen, the data processing apparatus to authenticate the user by address data and password data input via the input screen,

an obtaining unit that obtains, when the user is successfully authenticated by the data processing apparatus, as association data associated with the address data and the password data, tenant data, a user name of users who belong to a tenant of the tenant data and address data of each of the users, from the data processing apparatus to cause a storage unit to store the association data,

an accepting unit that, when displaying the input screen,

displays, when the association data is stored in the storage unit, a user list using the user name of each of the users in the input screen,

reads out, upon a selection of a user from the displayed user list, the address data corresponding to the selected user name, and

accepts an input of password data by omitting input of the read out address data from the input screen.

2. The data processing system according to claim 1 ,

wherein the service using apparatus further includes a switch unit that switches, in accordance with a content of a selection by the user in the input screen, a first input screen for inputting the address data and the password data and a second input screen, in which the user list is displayed, for accepting a selection of a user from the displayed user list.

3. The data processing system according to claim 2 ,

wherein the service using apparatus further includes a setting unit for setting whether to permit usage of the user list, and

wherein the switching unit only uses the first input screen when it is set that the usage of the user list is not permitted by the setting unit.

4. The data processing system according to claim 2 ,

wherein the accepting unit accepts a request to add an account via the first input screen, and

wherein the data processing apparatus registers address data and password data corresponding to the request to add the account obtained by the accepting unit, and updates the user list.

5. The data processing system according to claim 1 ,

wherein the service using apparatus includes a password generating unit that generates an apparatus authentication password,

wherein the data processing apparatus further includes

a ticket generating unit that generates an apparatus authentication ticket from the apparatus authentication password generated by the password generating unit, and

an access control unit that controls, using the apparatus authentication ticket generated by the ticket generating unit, access of the obtaining unit to obtain the user list.

6. The data processing system according to claim 1 ,

wherein the service using apparatus further includes an authentication unit that receives a request to authenticate from a user and authenticates the user, and

wherein the data processing apparatus provides a service to the service using apparatus based on user data of the user who is successfully authenticated by the authentication unit.

7. The data processing system according to claim 1 ,

wherein the service using apparatus deletes the stored association data periodically or by an instruction.

8. A data processing method performed by a data processing system including

a service using apparatus, and

a data processing apparatus that provides a service to the service using apparatus,

the method comprising:

performed by the service using apparatus,

an authentication request step of requesting, based on a request to authenticate from a user accepted via an input screen, the data processing apparatus to authenticate the user by address data and password data input via the input screen;

an obtaining step of obtaining, when the user is successfully authenticated by the data processing apparatus, as association data associated with the address data and the password data, tenant data, a user name of users who belong to a tenant of the tenant data and address data of each of the users, from the data processing apparatus to cause a storage unit to store the association data; and

an accepting step of, when displaying the input screen,

displaying, when the association data is stored in the storage unit, a user list using the user name of each of the users in the input screen,

reading out, upon a selection of a user from the displayed user list, the address corresponding to the selected user, and

accepting an input of password data by omitting input of the read out address data from the input screen.