Data In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpret ...

in use is an

information technology Information technology (IT) is the use of computers to create, process, store, retrieve, and exchange all kinds of data . and information. IT forms part of information and communications technology (ICT). An information technology syste ...

term referring to active data which is stored in a non-persistent digital state typically in computer

random-access memory Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost the ...

(RAM),

CPU cache A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, whi ...

s, or

CPU register A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. ...

Scranton, PA Scranton is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Lackawanna County. With a population of 76,328 as of the 2020 U.S. census, Scranton is the largest city in Northeastern Pennsylvania, the Wyoming Vall ...

data scientist Daniel Allen in 1996 proposed ''Data in use'' as a complement to the terms ''

data in transit Data in transit, also referred to as data in motion and data in flight, is data en route between source and destination, typically on a computer network. Data in transit can be separated into two categories: information that flows over the publi ...

'' and '' data at rest'' which together define the three states of

digital data Digital data, in information theory and information systems, is information represented as a string of discrete symbols each of which can take on one of only a finite number of values from some alphabet, such as letters or digits. An exampl ...

Alternative definitions

Data in use refers to data in computer memory. Some cloud

software as a service Software as a service (SaaS ) is a software licensing and delivery model in which software is licensed on a subscription basis and is centrally hosted. SaaS is also known as "on-demand software" and Web-based/Web-hosted software. SaaS is co ...

(SaaS) providers refer to data in use as any data currently being processed by applications, as the CPU and memory are utilized.

Concerns

Because of its nature, data in use is of increasing concern to businesses, government agencies and other institutions. Data in use, or memory, can contain sensitive data including digital certificates, encryption keys, intellectual property (software algorithms, design data), and

personally identifiable information Personal data, also known as personal information or personally identifiable information (PII), is any information related to an identifiable person. The abbreviation PII is widely accepted in the United States, but the phrase it abbreviates ha ...

. Compromising data in use enables access to encrypted data at rest and data in motion. For example, someone with access to random access memory can parse that memory to locate the encryption key for data at rest. Once they have obtained that encryption key, they can decrypt encrypted data at rest. Threats to data in use can come in the form of

cold boot attack In computer security, a cold boot attack (or to a lesser extent, a platform reset attack) is a type of side channel attack in which an attacker with physical access to a computer performs a memory dump of a computer's random-access memory (RAM) b ...

s, malicious hardware devices,

rootkit A rootkit is a collection of computer software, typically malicious, designed to enable access to a computer or an area of its software that is not otherwise allowed (for example, to an unauthorized user) and often masks its existence or the exis ...

s and bootkits.

Full memory encryption

Encryption, which prevents data visibility in the event of its unauthorized access or theft, is commonly used to protect Data in Motion and Data at Rest and increasingly recognized as an optimal method for protecting Data in Use. There have been multiple projects to encrypt memory. Microsoft

Xbox Xbox is a video gaming brand created and owned by Microsoft. The brand consists of five video game consoles, as well as applications (games), streaming services, an online service by the name of Xbox network, and the development arm by the ...

systems are designed to provide memory encryption and the company

PrivateCore PrivateCore is a venture-backed startup located in Palo Alto, California that develops software to secure server data through server attestation and memory encryption. The company's attestation and memory encryption technology fills a gap that e ...

presently has a commercial software product vCage to provide attestation along with full memory encryption for x86 servers.GCN, John Moore, March 12, 2014:"How to lock down data in use -- and in the cloud"
/ref> Several papers have been published highlighting the availability of security-enhanced x86 and ARM commodity processors.M. Henson and S. Taylo
"Beyond full disk encryption:protection on security-enhanced commodity processors"
"Proceedings of the 11th international conference on applied cryptography and network security", 2013 In that work, an

ARM Cortex-A8 The ARM Cortex-A8 is a 32-bit processor core licensed by ARM Holdings implementing the ARMv7-A architecture. Compared to the ARM11, the Cortex-A8 is a dual-issue superscalar design, achieving roughly twice the instructions per cycle. The Cortex ...

processor is used as the substrate on which a full memory encryption solution is built. Process segments (for example, stack, code or heap) can be encrypted individually or in composition. This work marks the first full memory encryption implementation on a mobile general-purpose commodity processor. The system provides both confidentiality and integrity protections of code and data which are encrypted everywhere outside the CPU boundary. For x86 systems, AMD has a Secure Memory Encryption (SME) feature introduced in 2017 with

Epyc Epyc is a brand of multi-core x86-64 microprocessors designed and sold by AMD, based on the company's Zen microarchitecture. Introduced in June 2017, they are specifically targeted for the server and embedded system markets. Epyc processors share ...

. Intel has promised to deliver its Total Memory Encryption (TME) feature in an upcoming CPU.

CPU-based key storage

Operating system kernel patches such as TRESOR and Loop-Amnesia modify the operating system so that CPU registers can be used to store encryption keys and avoid holding encryption keys in RAM. While this approach is not general purpose and does not protect all data in use, it does protect against cold boot attacks. Encryption keys are held inside the CPU rather than in RAM so that data at rest encryption keys are protected against attacks that might compromise encryption keys in memory.

Enclaves

Enclaves enable an “enclave” to be secured with encryption in RAM so that enclave data is encrypted while in RAM but available as clear text inside the CPU and CPU cache. Intel Corporation has introduced the concept of “enclaves” as part of its Software Guard Extensions. Intel revealed an architecture combining software and CPU hardware in technical papers published in 2013.

Cryptographic protocols

Several cryptographic tools, including secure multi-party computation and

homomorphic encryption Homomorphic encryption is a form of encryption that permits users to perform computations on its encrypted data without first decrypting it. These resulting computations are left in an encrypted form which, when decrypted, result in an identical ...

, allow for the private computation of data on untrusted systems. Data in use could be operated upon while encrypted and never exposed to the system doing the processing.

References

{{Reflist Computer data Cryptography