A method includes a first computing device encrypting a portion of a data matrix based on a set of encryption keys to produce an encrypted data matrix. The method further includes the first computing device sending the encrypted data matrix to a second computing device. The method further includes the second computing device dispersed storage error encoding the data matrix to produce a set of encrypted encoded data slices. The method further includes the second computing device sending the set of encrypted encoded data slices to a set of storage units of the DSN for storage therein.