1. A client computer for updating a database stored on a server via a network, the client computer comprising: a network interconnect to communicate with the server via the network to update the database, wherein the database comprises first data items and suffix items, each one of the suffix items describes a suffix of at least one first data item of the first data items, and for each suffix item a first referential connection exists in the database assigning said suffix item to the at least one first data item of the first data items that comprises the suffix of said suffix item, each suffix item is encrypted with a suffix cryptographic key in the database, each first data item is encrypted with a first cryptographic key in the database; a microprocessor to execute an application program stored at a non-transitory processor-readable medium, the application program configured to: a) receive an update first data item, the update first data item comprising a set of successional symbols, b) creating create an update suffix item by removing a number of the set of successional symbols from the left side of the update first data item, the update suffix item being the residual part of the update first data item without the removed symbols, c) encrypt the update suffix item with the suffix cryptographic key for obtaining an encrypted update suffix item and encrypting the update first data item with the first cryptographic key for obtaining an encrypted update first data item, d) provide a storage request to the database, the storage request comprising instructions to store in the database the encrypted update suffix item, the encrypted update first data item and the first referential connection assigning said encrypted update suffix item to the encrypted update first data item, e) repeat steps b)-d) with different numbers of the successional removed symbols, the numbers being in between a minimum and a maximum, wherein the maximum is given by the total number of symbols of the update first data item minus a predefined minimal word length.
7. The client computer of claim 1 , wherein a data item is given by the update first data item or the update suffix item, wherein the application program is further operational to determine for each data item the respective cryptographic key required for encrypting said data item by generating a seed value and combining the seed value with a symmetric key common for all of the data items, wherein the storage request comprises instructions to store in the database the data item with the seed value being appended to the encrypted data item, wherein the seed value being appended to the encrypted data item forms a storable encrypted data item, wherein the seed value is appended to the data suffix item in a predefined manner common for all data items.