A method for encrypting data. The method comprises receiving, from a user, via a client terminal, digital content including at least one textual string for filling in at least one field in a document managed by a network node via a computer network, encrypting the at least one textual string, and sending the at least one encrypted textual string to the network node via the computer network so as to allow filling in the at least one field with the at least one encrypted textual string. The network node is configured for storing and retrieving the at least one textual encrypted string without decrypting.