Microsoft Technology Licensing, LLC

Ravi Ramamurthy

Donald Kossmann

Panagiotis Antonopoulos

Arvind Arasu

Kenneth Hiroshi Eguro

Raghav Kaushik

Aditya Nigam

Nikhil Vithlani

Surajit J Chaudhuri

Vivek Ravindranath Narasayya

Cesar Alejandro Galindo-Legaria

Joachim Hammer

Michael I Zwilling

Bala Neerumalla

Jakub J Szymaszek

Leo Giakoumakis

Kedar Dubhashi

Donald Alan Kossmann

A 'Database Confidentiality System' provides various techniques for using server-side trusted computing in combination with configurable type metadata and user- or system-definable rules associated with individual database fields to implement database confidentiality. In various implementations, type metadata and one or more rules are added to each database field. Metadata includes a domain, method of encryption, and a pointer to an encryption key used to encrypt the data in the corresponding field. The rules define one or more operations allowed on the corresponding data types. The type metadata and rules are optionally integrity protected and/or encrypted to avoid unauthorized changes or access. Various encryption techniques (e.g., probabilistic, Paillier, etc.) allow some computations to be performed in an untrusted environment without access to the encryption key. This enables the Database Confidentiality System to maintain database confidentiality while performing distributed computation and communications between the untrusted machine and the trusted machine.

Type-based database confidentiality using trusted computing

Computer systems, devices, and associated methods of evaluating an expression comprising restricted data are disclosed herein. In one embodiment, a method includes receiving a database statement from a client application and verifying the authenticity of the database statement. If the database statement is authentic, an approved expression is identified in the database statement for creating an evaluation rule. The method further includes restricting evaluation of expressions in a protected computing environment according to the created evaluation rule.

Expression evaluation of database statements for restricted data

Computer systems, devices, and associated methods of optimizing the execution of instructions of a database statement by a database server are disclosed herein. In one embodiment, a method includes identifying a potential execution plan for executing instructions of the database statement and estimating a cost for executing the execution plan. The cost can comprise an encrypted data processing cost associated with a operation in the execution plan of executing an operation on encrypted data in a protected computing environment. The method can include estimating the encrypted data processing cost in the protected computing environment based on statistics generated in the protected computing environment about a database table. In response to estimating the cost for executing the execution plan, comparing the cost to estimated costs of alternative execution plans, selecting the lowest-cost plan for execution, and executing the lowest-cost execution plan.

Execution optimization of database statements involving encrypted data

Technology is described for transformation rule profiling for a query optimizer. The method can include obtaining a database query configured to be optimized by the query optimizer of a database system. An optimized query plan for the database query can be found using a host set of transformation rules. One transformation rule can be removed and checked at a time. Each transformation rule can be checked to determine whether the transformation rule affects an optimal query plan output. A test query plan can be generated after each transformation rule has been removed. The query optimizer can determine whether the test query plan is different than the optimized query plan in the absence of the removed transformation rule. An equivalent set of transformation rules can be created that includes transformation rules where the test query plan generated from the equivalent set of transformation rules is equivalent to the optimized plan.

Transformation rule profiling for a query optimizer

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Redmond, WA, United States of America

Ravi Ramamurthy