An authentication system comprising: a terminal; and an information processing apparatus communicable with the terminal via a network, the authentication system being configured to perform authentication of a user who operates the information processing apparatus, wherein the information processing apparatus includes: a first accepting unit (20F1) configured to accept user information for use in authentication of the user, wherein the user information is a user ID; a second accepting unit (20F2) configured to accept terminal information for use in identification of the terminal; and a user information transmission unit (20F3) configured to identify the terminal based on the terminal information and transmit the user information to the terminal, and the terminal includes: a storage unit (30F1) configured to store a job designated by the user; a reception unit (30F2) configured to receive the user information from the information processing apparatus; and an authentication unit (30F3) configured to perform authentication of the user based on the user information received by the reception unit (30F2), a transmission unit (30F4) configured to transmit job information regarding the job to the information processing apparatus based on the performed authentication, wherein the information processing apparatus further comprises an information storage unit (20F4) configured to store second user information in association with first user information, the first user information being the user information, the second user information being different from the first user information, wherein the second user information is a medium ID, in response to accepting the first user information by the first accepting unit (20F1), the information processing apparatus identifies the second user information based on the first user information, and the user information transmission unit (20F3) transmits the first user information and the second user information, as the user information. a terminal; and an information processing apparatus communicable with the terminal via a network, the authentication system being configured to perform authentication of a user who operates the information processing apparatus, wherein the information processing apparatus includes: a first accepting unit (20F1) configured to accept user information for use in authentication of the user, wherein the user information is a user ID; a second accepting unit (20F2) configured to accept terminal information for use in identification of the terminal; and a user information transmission unit (20F3) configured to identify the terminal based on the terminal information and transmit the user information to the terminal, and a first accepting unit (20F1) configured to accept user information for use in authentication of the user, wherein the user information is a user ID; a second accepting unit (20F2) configured to accept terminal information for use in identification of the terminal; and a user information transmission unit (20F3) configured to identify the terminal based on the terminal information and transmit the user information to the terminal, and the terminal includes: a storage unit (30F1) configured to store a job designated by the user; a reception unit (30F2) configured to receive the user information from the information processing apparatus; and an authentication unit (30F3) configured to perform authentication of the user based on the user information received by the reception unit (30F2), a storage unit (30F1) configured to store a job designated by the user; a reception unit (30F2) configured to receive the user information from the information processing apparatus; and an authentication unit (30F3) configured to perform authentication of the user based on the user information received by the reception unit (30F2), a transmission unit (30F4) configured to transmit job information regarding the job to the information processing apparatus based on the performed authentication, wherein the information processing apparatus further comprises an information storage unit (20F4) configured to store second user information in association with first user information, the first user information being the user information, the second user information being different from the first user information, wherein the second user information is a medium ID, in response to accepting the first user information by the first accepting unit (20F1), the information processing apparatus identifies the second user information based on the first user information, and the user information transmission unit (20F3) transmits the first user information and the second user information, as the user information.