1. A data deduplication method for execution by a computing device, wherein the method comprises: receiving a storage request regarding storing a data object in dispersed storage network (DSN) memory; determining a data portion of the data object; determining that a substantially identical data portion is stored in the DSN memory; obtaining an encryption pattern sequence for the data portion; retrieving an encryption key from the DSN memory, wherein at least a portion of the encryption key is substantially identical to at least a portion of the data portion; encrypting the data portion using the encryption key and the encryption pattern sequence to produce an encrypted data portion that includes a plurality of encrypted data segments; compressing the encrypted data portion using a pattern based data compression function to produce a compressed data portion; and facilitating storage of the compressed data portion and the encryption pattern sequence in response to the storage request.