Página 4 dos resultados de 8247 itens digitais encontrados em 0.025 segundos
Resultados filtrados por Publicador: Massachusetts Institute of Technology

Dynamic security for medical record sharing

Cody, Patrick M. (Patrick Michael), 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 53 p.; 3234030 bytes; 3238342 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
47.177%
Information routinely collected by health care organizations is used by researchers to analyze the causes of illness and evaluate the effectiveness of potential cures. Medical information sharing systems are built to encourage hospitals to contribute patient data for use in clinical studies. These organizations possess a wide variety of environments and risk assessments, and require sufficient assurances of patient privacy. This thesis introduces mechanisms to dynamically generate an applicable security policy for medical information sharing systems. We present implementation-independent mechanisms that are capable of interoperating with different security settings at different sites to produce security configurations with significantly different characteristics and vulnerabilities. We also present a rules-based agent to assist in the selection process. This approach gives maximum freedom to generate the appropriate system according to the tradeoffs between cost, patient privacy, and data accessibility.; by Patrick M. Cody.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.; Includes bibliographical references (p. 52-53).

Enhancing availability and security through boundless memory blocks

Cadar, Cristian
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 52 leaves; 2070965 bytes; 2071920 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
47.08393%
We present a new technique, boundless memory blocks, that automatically eliminates buffer overflow errors, enabling programs to continue to execute through memory errors without memory corruption. Buffer overflow vulnerabilities are caused by programming errors that allow an attacker to cause the program to write beyond the bounds of an allocated memory block to corrupt other data structures. The standard way to exploit a buffer overflow vulnerability involves a request that is too large for the buffer intended to hold it. The buffer overflow error causes the program to write part of the request beyond the bounds of the buffer, corrupting the address space of the program and causing the program to execute injected code contained in the request. Our boundless memory blocks compiler inserts checks that dynamically detect all out of bounds accesses. When it detects an out of bounds write, it stores the value away in a hash. Our compiler can then return the stored value as the result of an out of bounds read to that address. In the case of uninitialized addresses, our compiler simply returns a predefined value. We have acquired several widely used open source applications (Apache, Sendmail, Pine, Mutt, and Midnight Commander). With standard compilers...

Mandatory security and performance of services in Asbestos

Ziegler, David Patrick
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 66 p.; 2890479 bytes; 2893146 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
47.08393%
This thesis presents the design and implementation for several system services, including network access and database storage, on a new operating system design, Asbestos. Using the security mechanism provided by Asbestos, Asbestos labels, these services are used to support the construction of secure Web applications. The network and database services serve as the foundation for a Web server that supports mandatory security policies, such that even a compromised Web application cannot improperly disclose private data. The methods used in this thesis allow Web application developers to be freed from worries about flawed applications, if developers are willing to place trust in the underlying services used.; by David Patrick Ziegler.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.; Includes bibliographical references (p. 61-66).

CargoNet : micropower sensate tags for supply-chain management and security; Micropower sensate tags for supply-chain management and security

Malinowski, Mateusz Ksawery
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 113 p.
Português
Relevância na Pesquisa
47.08393%
This thesis describes the development of a system of sensate active RFID tags for supply-chain management and security applications, necessitated by the current lack of commercial platforms capable of monitoring the state of shipments at the crate and case level. To make a practical prototype, off-the-shelf components and custom-designed circuits that minimize power consumption and cost were assembled and integrated into an interrupt-driven, quasi-passive system that can monitor, log, and report environmental conditions inside a shipping crate while consuming only 23.7 microwatts of average power. To prove the feasibility of the system, the tags were tested in the laboratory and aboard transport conveyances.; by Mateusz Ksawery Malinowski.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.; Includes bibliographical references (p. 109-113).

Security proofs for the MD6 hash function mode of operation

Crutchfield, Christopher Yale
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 84 p.
Português
Relevância na Pesquisa
47.08393%
In recent years there have been a series of serious and alarming cryptanalytic attacks on several commonly-used hash functions, such as MD4, MD5, SHA-0, and SHA1 [13, 38]. These culminated with the celebrated work of Wang, Yin, and Yu from 2005, which demonstrated relatively efficient methods for finding collisions in the SHA-1 hash function [37]. Although there are several cryptographic hash functions - such as the SHA-2 family [28] - that have not yet succumbed to such attacks, the U.S. National Institute of Standards and Technology (NIST) put out a call in 2007 for candidate proposals for a new cryptographic hash function family, to be dubbed SHA-3 [29]. Hash functions are algorithms for converting an arbitrarily large input into a fixed-length message digest. They are typically composed of a compression function or block cipher that operate on fixed-length pieces of the input and a mode of operation that governs how apply the compression function or block cipher repeatedly on these pieces in order to allow for arbitrary-length inputs. Cryptographic hash functions are furthermore required to have several important and stringent security properties including (but not limited to) first-preimage resistance, second-preimage resistance...