Secure storage of and access to files through a web application

A method for cryptographically secure storing of a file using a web application executed by a web browser on a user computer system of a user, the method comprising

• invoking the web application from a web server computer system over a network by the web browser on the user computer system,
• encrypting the file with a cryptographic key on the user computer system using the web application,
• providing a distribution plan by the web application, wherein the distribution plan comprises instructions for fragmenting the file into a plurality of file fragments by means of an error correction method and identifiers of a plurality of mutually independent storage services in whose non-volatile storage media the generated file fragments are to be stored,
• fragmenting the encrypted file on the user computer system by the web application into a plurality of file fragments by the error correction method according to the distribution plan, wherein at least one of the file fragments includes error correction bits,
• sending the resulting file fragments by the web application over the network to the storage services identified by the distribution plan, wherein an authorization token is provided by the web server computer system for each of the storage services as proof of authorization to store the corresponding file fragment.

A web server computer system comprising a processor, a network interface for operatively coupling the web server computer system to a user computer system, the web server computer system comprising a storage medium containing program instructions, wherein the program instructions are configured, when executed by the processor, to send program instructions for executing the web application in a web browser on the user computer system over the network to the user computer system in response to receiving an invocation of a web application from a web browser on the user computer system over the network, wherein the web application is configured to perform the following method for cryptographically secure storing a file:

• encrypting the file with a cryptographic key on the user computer system using the web application,
• providing a distribution plan by the web application, the distribution plan comprising instructions for fragmenting the file into a plurality of file fragments by means of an error correction method and identifiers of a plurality of storage services in whose non-volatile storage media the generated file fragments are to be stored,
• fragmenting the encrypted file on the user computer system by the web application into a plurality of file fragments by the error correction method according to the distribution plan, wherein at least one of the file fragments includes error correction bits,
• sending the resulting file fragments by the web application over the network to the storage services identified by the distribution plan, wherein an authorization token is provided by the web server computer system for each of the storage services as proof of authorization to store the corresponding file fragment.