Storage of cryptographically-split data blocks at geographically-separated locations

An electronic computing device for securely storing and retrieving data, the electronic computing system comprising:

• a primary interface that receives a primary write request that specifies a primary data block to be written to a primary storage location;
• a write module that causes the electronic computing device to cryptographically split the primary data block into a plurality of secondary data blocks such that the primary data block can be reconstructed using any subset of the secondary data blocks that includes at least a minimum number of secondary data blocks and cannot be reconstructed using any subset of the secondary data blocks that includes fewer than the minimum number of secondary data blocks, wherein the minimum number of secondary data blocks is less than or equal to a total number of the secondary data blocks;
• and
• a secondary interface that sends secondary write requests to a plurality of storage devices at a plurality of geographically-separated sites, each of the secondary write requests instructing a different one of the storage devices to store a different one of the secondary data blocks, wherein each of the sites stores at most the minimum number of secondary data blocks.

A computer-readable storage medium comprising instructions that, when executed by an electronic computing device, cause the electronic computing device to:

• receive a first primary write request from a client computing device via an electronic communications network, the first primary write request specifying a first primary data block to be written to a first primary storage location of a first volume;
• cryptographically split the first primary data block into a first plurality of secondary data blocks such that the first primary data block can be reconstructed using any subset of the secondary data blocks that includes at least a minimum number of secondary data blocks in the first plurality of secondary data blocks and cannot be reconstructed using any subset of the secondary data blocks in the first plurality of secondary data blocks that includes fewer than the minimum number of secondary data blocks, wherein the minimum number of secondary data blocks is less than a total number of the secondary data blocks in the first plurality of secondary data blocks;
• send secondary write requests to different storage devices in a plurality of storage devices at a plurality of geographically-separated sites, each of the sites storing fewer than the minimum number of secondary data blocks in the first plurality of secondary data blocks;
• receive a second primary write request from the client computing device via the electronic communications network, the second primary write request specifying a second primary data block to be written to a primary storage location of a second volume;
• cryptographically split the second primary data block into a second plurality of secondary data blocks such that the second primary data block can be reconstructed using any subset of the secondary data blocks that includes at least the minimum number of secondary data blocks in the second plurality of secondary data blocks and cannot be reconstructed using any subset of the secondary data blocks in the second plurality of secondary data blocks that includes fewer than the minimum number of secondary data blocks, wherein the minimum number of secondary data blocks is less than a total number of the secondary data blocks in the second plurality of secondary data blocks;
• and
• send secondary write requests to different storage devices in the plurality of storage devices at the plurality of geographically-separated sites, each of the sites storing fewer than the minimum number of secondary data blocks in the second plurality of secondary data blocks.