Provided are a memory system, memory controller, and method for using a memory address to form a tweak key to use to encrypt and decrypt data. A base tweak co is generated as a function of an address of a block of data in the memory storage. For each sub-block of the block, performing: processing the base tweak to determine a sub-block tweak; combining the sub-block tweak with the sub-block to produce a modified sub-block; and performing an encryption operation comprising one of encryption or decryption on the modified sub-block to produce sub-block output comprising one of encrypted data and unencrypted data for the sub-block.