A file storage system comprising: a file storage apparatus to store a ciphertext which can be decrypted when attribute information set in the decryption key satisfies a decryption condition set in the ciphertext; and a user terminal to display a folder having the decryption condition as a folder name, and to encrypt using the decryption condition a file to be encrypted input to the folder by a drag and drop operation of a user, wherein the user terminal comprises: an attribute information transmission part to transmit the attribute information to the file storage apparatus, wherein the file storage apparatus comprises: a ciphertext storage part to store ciphertexts; a ciphertext extraction part to extract identifying information of a ciphertext of which a decryption condition is satisfied by the attribute information transmitted by the attribute information transmission part from among the ciphertexts stored by the ciphertext storage part; and a list transmission part to transmit a list indicating identifying information of the ciphertext extracted by the ciphertext extraction part to the user terminal, and wherein the user terminal further comprises: a list display part to display the identifying information, indicated by the list transmitted by the list transmission part, classified by decryption condition. a file storage apparatus to store a ciphertext which can be decrypted when attribute information set in the decryption key satisfies a decryption condition set in the ciphertext; and a user terminal to display a folder having the decryption condition as a folder name, and to encrypt using the decryption condition a file to be encrypted input to the folder by a drag and drop operation of a user, wherein the user terminal comprises: an attribute information transmission part to transmit the attribute information to the file storage apparatus, wherein the file storage apparatus comprises: a ciphertext storage part to store ciphertexts; a ciphertext extraction part to extract identifying information of a ciphertext of which a decryption condition is satisfied by the attribute information transmitted by the attribute information transmission part from among the ciphertexts stored by the ciphertext storage part; and a list transmission part to transmit a list indicating identifying information of the ciphertext extracted by the ciphertext extraction part to the user terminal, and wherein the user terminal further comprises: a list display part to display the identifying information, indicated by the list transmitted by the list transmission part, classified by decryption condition. an attribute information transmission part to transmit the attribute information to the file storage apparatus, wherein the file storage apparatus comprises: a ciphertext storage part to store ciphertexts; a ciphertext extraction part to extract identifying information of a ciphertext of which a decryption condition is satisfied by the attribute information transmitted by the attribute information transmission part from among the ciphertexts stored by the ciphertext storage part; and a list transmission part to transmit a list indicating identifying information of the ciphertext extracted by the ciphertext extraction part to the user terminal, and wherein the user terminal further comprises: a list display part to display the identifying information, indicated by the list transmitted by the list transmission part, classified by decryption condition. a ciphertext storage part to store ciphertexts; a ciphertext extraction part to extract identifying information of a ciphertext of which a decryption condition is satisfied by the attribute information transmitted by the attribute information transmission part from among the ciphertexts stored by the ciphertext storage part; and a list transmission part to transmit a list indicating identifying information of the ciphertext extracted by the ciphertext extraction part to the user terminal, and wherein the user terminal further comprises: a list display part to display the identifying information, indicated by the list transmitted by the list transmission part, classified by decryption condition.