1. A method for execution by a computing device, the method comprises: receiving a message to store a data object; determining at least a portion of the data object; generating an encryption key based on the at least a portion; determining a key reference of the encryption key; retrieving a prior encryption key with a similar key reference from dispersed storage network (DSN) memory; calculating a difference key based on the encryption key and the prior encryption key, the difference key calculated by subtracting the prior encryption key from the encryption key; and creating encryption key information including the difference key and the similar key reference of the prior encryption key; encrypting the portion of the data object utilizing the encryption key information in accordance with operational parameters; compressing the encrypted portion of the data object; sending the compressed encrypted portion of the data object as the encrypted data portion to an access module of a DS processing unit to create encoded data slices and store the encoded data slices in the DSN memory.