Method and system for reconstruction of a data object from distributed redundant data parts

A data object is encoded in a redundant code. The redundant code defines a decoding scheme for reconstructing the data object from a sub-set of the encoded data parts. At least the sub-set of the encoded data parts is encrypted using a homomorphic encryption scheme, which allows equivalents of the arithmetic operations of a reconstruction process to be performed on encrypted encoded data parts. The data parts are stored distributed over a plurality of source terminals of a communication network, for use by a target terminal of the communication network. Upon a retrieval command from the target terminal, an upload management module determines which source terminals are available and the upload management module determines causes a selected set of terminals to transmit the encrypted encoded data parts each via its own connection to the network to a decoder server. The decoder server performs homomorphic equivalent operations of arithmetic operations of the reconstruction process and downloads the results to the target terminal. In this way the target terminal does not need to perform the entire reconstruction, without requiring decryption outside the target terminal.