Embodiments herein describe a memory controller that performs in-line data processing (e.g., cryptography and error correction) and efficiently organizes data and associated metadata in memory. The memory controller generates a data block that includes a processed (e.g., encrypted) dataset and associated metadata (e.g., cryptographic metadata and ECC), and stores the data block in a block of memory (i.e., rather than storing the metadata separately), to minimize a number of access operations. The memory controller may access memory in segments (e.g., BL16 operations) that are smaller than the data blocks. For linear accesses, the memory controller may cache a portion of a data block until a subsequent access operation.