XTS

XTS is an acronym that can refer to several unrelated concepts. In cryptography, it most commonly denotes XTS mode, or XTS-AES, a disk-encryption mode designed for data-at-rest protection. XTS stands for XEX-based Tweaked CodeBook with ciphertext Stealing. The mode operates on 128-bit blocks and uses two AES keys (for example AES-128-XTS and AES-256-XTS correspond to total key lengths of 256 and 512 bits, respectively). Each data unit, typically a disk sector, is assigned a unique tweak (often the sector number) so that identical plaintext blocks encrypt to different ciphertext blocks, enabling random-access encryption without block-level repetition. XTS also employs ciphertext stealing to handle final partial blocks. XTS is defined in standards such as IEEE P1619 and NIST SP 800-38E, and has been widely adopted in full-disk encryption solutions.

While XTS-AES provides confidentiality for stored data, it does not by itself provide data integrity or authentication. Modern deployments commonly pair XTS with separate integrity protections or use authenticated encryption schemes for higher-assurance scenarios.

Beyond cryptography, XTS can denote other, unrelated uses or organizations, depending on context. Therefore, when encountering the acronym, the intended meaning should be inferred from the domain or accompanying description.