Cryptographic data storage

#The present disclosure relates to storing of data, such as confidential data, for example in a cloud service. When storing data and in particular confidential data in a cloud service or on a server, a typical problem is data security. A well-known solution to this problem is to encrypt the data. Most of the current systems use symmetric key encryption, allowing a user to keep the key private, so that the data can be accessed if needed.

#An issue with this rather simple approach is that sharing of such encrypted user data is not conveniently possible. The user has to provide the symmetric key to the intended recipient and make sure the transmission of the key itself is secure and that no eavesdropping occurred. In addition and once shared, the user has no control about access and dissemination of the affected data.

#The present inventors have ascertained that an object exists for storing and sharing in particular confidential data. The object is solved by the invention as defined in the independent claims. The dependent claims and the following description provides various embodiments of the invention.

#FIG. 1 shows a flow diagram of a first exemplary embodiment;

#FIG. 2 shows a flow diagram of a second exemplary embodiment; and

#FIG. 3 shows a flow diagram of a third exemplary embodiment.

#The present invention suggests multiple methods to share in particular confidential data.

#In the following, reference will be made to service data items, i.e., electronic data of any type, length, and content, e.g., a bit string, as defined in PCT application PCT/US2017/044729, entitled “COMPUTER-IMPLEMENTED METHOD AND SYSTEM OF TAMPER-EVIDENT RECORDING OF A PLURALITY OF SERVICE DATA ITEMS”, the contents of which application are incorporated herein for all purposes.

#In some embodiments, user data, i.e., one or more service data items, is partitioned into one or more data stores, hereinafter also referred to as “crypto buckets”. For example, a data store may be provided per service data item. In other examples, multiple service data items may be collectively stored in a given data store. In some embodiments, a data item verification fingerprint may be generated for each data store and then stored using the procedure, discussed in PCT/US2017/044729.